The following is an excerpt from Real Christianity, The Nature of the Church:
THE UPPER ROOM
Why did Jesus create His community of called-out ones in the humble upper room? For starters, He had to have a place off the beaten path, so to speak. It would have to be owned by a disciple or a disciple’s family who was sympathetic to the cause. It could not be a public place, such as the temple complex, but private, to allow for complete unity of spirit and purpose. It had to be a place big enough for 120 people to pray and seek God for about ten days without interruption. In short, it had to be a house. In reality, it was a house.
Though we cannot yet be positively certain, particular statements in Scripture lead one to the strong conclusion that it was located on Mount Zion, Jerusalem’s highest southwestern hill, and that it was probably the house of Mary, the mother of John Mark. If placed on Mount Zion, this house would be located roughly a half mile due southwest of the Temple Mount, approximately five hundred feet south of the present Zion gate. At the time of the Qahal’s creation, however, this house was within Jerusalem proper since the southern wall of the city was located further to the south. Therefore, though Jesus was betrayed, died, was entombed, and rose again outside the city walls, He created the Church inside the city. Not only that, He created the Church in a house.
Why did He create the Church in the city that condemned Him to death? If it had to be within Jerusalem, why didn’t He create the Qahal in a place of high honor, such as the temple? Was it because He was rejected by the ruling hierarchy? Was it because there was no place of high honor for the Lord of all Creation? Or was it because Jesus simply created His community in the most appropriate of all dwelling places, a place which had been foretold in Scripture?
You will bring them and plant them
in the mountain of Your inheritance,
The place, O LORD,
which You have made for Your dwelling,
The sanctuary, O LORD,
which Your hands have established.
The LORD shall reign
forever and ever. 
THE HOUSE OF GOD
From the untold millions which had descended from Abraham by the first century A.D., only the upper-roomers were present when this scripture was fulfilled. Each and every one of these original 120 were Jews. On the birthday of the Lord’s Qahal, Jesus established a sanctuary, a dwelling place on His own mountain—Mount Zion. On this mountain, the 120 were planted, both in the Lord and by the Lord, and functioned as the ovum fertilized by the Holy Spirit which would eventually develop into a body—the body of Christ. Before the sun went down that first day, the original 120 grew by twenty-five times to three thousand—all Jews, all descendants of Abraham, all devout and God-fearing, from every country under heaven to which they had been dispersed. Even though Luke, the author of the book of Acts, doesn’t say so specifically, can there be any doubt that each tribe of Israel was represented in the initial outpouring?
This was the mysterious destiny of the house of Israel—to one day become the actual dwelling place of YHWH!
When Abraham was first called forth and told he would be the progenitor of many people, God had His own future residence in mind. Later, He revealed this truth to Moses, who led God’s people to the land of promise. The house of God would only be a home for the obedient, however, since they would be sharing quarters with God Himself. The structure of the tabernacle of Moses reveals to us The Nature of the Church. The tabernacle was a tent, mobile, following after the Lord as He moved onward into the future. It was filled with His presence. It was where the ark of the covenant was kept. The priests would minister in its midst. Sacrifice was called for. Repentance, baptism, and the infilling of His Spirit were all typed into its construction. It was pliable and moveable, built for eternal purposes.
The tabernacle and all the rites associated with it continued to the time of David. It was then that God revealed to yet another generation the purpose of the tent, and the great revelation of its underlying meaning. After building his own house, David desired to build a house for God. But the Lord would not. God’s plans had not changed, nor would they ever. His eternal purpose was wrapped up in the illustration of the mobile tent. In the future, His dwelling place would be similar—it would be within humanity. 
 Acts 12:12
 Exodus 15:17–18
 Pages 281-284 Real Christianity, The Nature of the Church © 2001 by RJ Dawson. All Rights Reserved.
“You did not choose Me but I chose you, and appointed you that you would go and bear fruit, and that your fruit would remain, so that whatever you ask of the Father in My name He may give to you.” [John 15:16]
Most of the people who refer to themselves as some form of “Christian” choose God on their terms. But God chooses real Christians on His terms. Thus, unreal Christians create their own unholy covenant with God according to their own stipulations and provisos. It is not a real covenant, though, because God is not involved in it. He signed none of the papers. He did not agree to the terms. Such minor details do not concern the pretenders, however. They continue onward by themselves insisting God is with them. And these people preach about the Jews being stiff-necked?
Many “Christians” have been duped into thinking they have the power to choose Messiah Jesus as their Lord and Savior. But Christians don’t do the choosing. What they do, before they become real Christians, is have a hungry heart for truth and light. They know there must be something much more than this temporal world of sin. As a result they begin searching for that “something more.” In the process they find belief systems, gurus, false forms of Christianity, and eastern religions that look real and are quite promising. But after looking within these and practicing their tenets for a while, they continue to move on because there is no heart connection. They do not feel fulfilled. They are not satisfied. Something is missing. Knowing this, they realize they have identified yet another fake. Most people in the world are content with fakes, but real searchers of truth never allow this for themselves. They continue seeking, not knowing God is attracting them magnetically by His Spirit until they are chosen.
For consider your calling, brethren, that there were not many wise according to the flesh, not many mighty, not many noble; but God has chosen the foolish things of the world to shame the wise, and God has chosen the weak things of the world to shame the things which are strong, and the base things of the world and the despised God has chosen, the things that are not, so that He may nullify the things that are, so that no man may boast before God. [1 Corinthians 1:26-29]
Among every pagan nation in the ancient world, each dwelling in deep darkness and rebellion, God chose one nation to represent Himself:
For you are a holy people to the LORD your God; the LORD your God has chosen you to be a people for His own possession out of all the peoples who are on the face of the earth. The LORD did not set His love on you nor choose you because you were more in number than any of the peoples, for you were the fewest of all peoples, but because the LORD loved you and kept the oath which He swore to your forefathers, the LORD brought you out by a mighty hand and redeemed you from the house of slavery, from the hand of Pharaoh king of Egypt. Know therefore that the LORD your God, He is God, the faithful God, who keeps His covenant and His lovingkindness to a thousandth generation with those who love Him and keep His commandments; but repays those who hate Him to their faces, to destroy them; He will not delay with him who hates Him, He will repay him to his face. [Deuteronomy 7:6-10]
Fifteen hundred years later, the very nation He called forth to be His own rejected Him. It became the opposite of faithful. It no longer loved Him or kept His commandments. It chose to hate its own Messiah.
“Jerusalem, Jerusalem, who kills the prophets and stones those who are sent to her! How often I wanted to gather your children together, the way a hen gathers her chicks under her wings, and you were unwilling. Behold, your house is being left to you desolate! For I say to you, from now on you will not see Me until you say, ‘BLESSED IS HE WHO COMES IN THE NAME OF THE LORD!’” [Matthew 23:37-39]
There was always a believing Remnant, however. In the first century, the Lord Jesus managed to gather together the hungry in heart and those searching for truth among His people. He chose them because of their condition of heart. With 120 people, including the remaining original eleven apostles and His own mother, He created His own community. These were people who loved and honored Him, who recognized Him for who He is, and who pledged their lives to serve, obey, and trust Him forever. They are the chosen of the Chosen.
“Then a voice came out of the cloud, saying, “This is My Son, My Chosen One; listen to Him!” [Luke 9:35]
He chose many more after Peter delivered the first message of the Qahal:
So then, those who had received his word were baptized; and that day there were added about three thousand souls. [Acts 2:41]
Can you hear the echo in the writings of Isaiah?
Behold, I will do something new, now it will spring forth; will you not be aware of it? I will even make a roadway in the wilderness, rivers in the desert. The beasts of the field will glorify Me, the jackals and the ostriches, because I have given waters in the wilderness and rivers in the desert, to give drink to My chosen people. The people whom I formed for Myself will declare My praise.
Yet you have not called on Me, O Jacob; but you have become weary of Me, O Israel. You have not brought to Me the sheep of your burnt offerings, nor have you honored Me with your sacrifices. I have not burdened you with offerings, nor wearied you with incense. You have bought Me not sweet cane with money, nor have you filled Me with the fat of your sacrifices; rather you have burdened Me with your sins, You have wearied Me with your iniquities. I, even I, am the one who wipes out your transgressions for My own sake, and I will not remember your sins. Put Me in remembrance, let us argue our case together; state your cause, that you may be proved right. Your first forefather sinned, and your spokesmen have transgressed against Me. So I will pollute the princes of the sanctuary, and I will consign Jacob to the ban and Israel to revilement. [Isaiah 43:19-28]
Was it just a coincidence that what was left of the geographic kingdom of David was utterly ruined forty years after the nation rejected their Savior? Was it coincidence that Jerusalem was razed and the Temple destroyed in 70AD?
Prior to this, He had made a Way for His real people, whether Jew or Gentile. He established a New Covenant. For forty years He continued adding thousands of believing Israelites, creating a new spiritual nation, as He said He would do through the prophets of old:
“Behold, days are coming,” declares the LORD, “when I will make a new covenant with the house of Israel and with the house of Judah, not like the covenant which I made with their fathers in the day I took them by the hand to bring them out of the land of Egypt, My covenant which they broke, although I was a husband to them,” declares the LORD. “But this is the covenant which I will make with the house of Israel after those days,” declares the LORD, I will put My law within them and on their heart I will write it; and I will be their God, and they shall be My people.” [Jeremiah 31:31-33]
“Moreover, I will give you a new heart and put a new spirit within you; and I will remove the heart of stone from your flesh and give you a heart of flesh. I will put My Spirit within you and cause you to walk in My statutes, and you will be careful to observe My ordinances.” [Ezekiel 36:26-27]
As most “Christians” reject the Lord, so did most Jews initially reject the Lord. But of those who accepted the invitation to the kingdom, Peter says:
And coming to Him as to a living stone which has been rejected by men, but is choice and precious in the sight of God, you also, as living stones, are being built up as a spiritual house for a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ. For this is contained in Scripture: “BEHOLD, I LAY IN ZION A CHOICE STONE, A PRECIOUS CORNER stone, AND HE WHO BELIEVES IN HIM WILL NOT BE DISAPPOINTED.” This precious value, then, is for you who believe;
But for those who disbelieve, “THE STONE WHICH THE BUILDERS REJECTED, THIS BECAME THE VERY CORNER stone,” and, “A STONE OF STUMBLING AND A ROCK OF OFFENSE;” for they stumble because they are disobedient to the word, and to this doom they were also appointed.
But you are A CHOSEN RACE, A royal PRIESTHOOD, A HOLY NATION, A PEOPLE FOR God’s OWN POSSESSION, so that you may proclaim the excellencies of Him who has called you out of darkness into His marvelous light; for you once were NOT A PEOPLE, but now you are THE PEOPLE OF GOD; you had NOT RECEIVED MERCY, but now you have RECEIVED MERCY. [1 Peter 2:4-10]
There are only two kinds of people in the world—those who are chosen by the Lord Jesus as members of the New Covenant and those who are not. Real Christians are not only called by the Lord and chosen for His community, they are also faithful and true warriors. Non-members of the New Covenant oppose it.
These will wage war against the Lamb, and the Lamb will overcome them, because He is Lord of lords and King of kings, and those who are with Him are the Called and Chosen and Faithful.” [Revelation 17:6-14] 
© 2012 by RJ Dawson. All Rights Reserved. [Part 3]
 Unless otherwise noted all Scriptures are taken from the New American Standard Bible, © 1960, 1963, 1968, 1971, 1972, 1973, 1975, 1977, 1995 by The Lockman Foundation. Used by permission.