After His resurrection, why did the Lord speak of the Kingdom rather than the Assembly (see Acts 1: 3), despite having previously said "I will build my assembly" (Matt. 16: 18)?
In the same passage in Matthew the Lord had also told Peter “ I will give to thee the keys of the kingdom of the heavens” (v19). The immediate need for the disciples was the truth of the Kingdom, not the truth of the Assembly. This was because Israel was not as yet set aside in judgment, there being still the possibility of national repentance and the Kingdom established in fulfilment of prophecy. This is proved by the disciples question in Acts 1: 6.
Many believe that the Assembly in its final form (as given in the prison epistles) is identical in every way to its form at Pentecost, but this view is untenable and genders confusion. The Assembly as presented to us in Ephesians, Colossians etc. has changed considerably from that of Acts 2. The concept of Gentile and Jew “made both one” and “joint heirs” (Eph. 2: 14; 3: 6) was completely unknown in the early history of Acts. Indeed, the Gospel was initially only preached to Jews (see Acts 11: 19). When God “opened a door of faith to the nations” (Acts 14: 27) this was within the prophetic teaching of the OT (see Rom. 15: 8–13) and many wanted the Gentile converts circumcised, making them effectively Jewish proselytes (see Acts 15: 1). This idea was rejected by the apostles, not by presenting the present truth of the “one body” (Eph. 2: 16), but by quoting from Amos 9: 11, 12. This prophecy refers to the time when the Gentiles who turn to God would be blessed in the Kingdom. It has nothing to do with the Assembly, for the Assembly is unknown in the OT.
The unique feature of the Assembly, Gentile and Jew in one body united to the Lord as Head in heaven, was unknown in the OT. This mystery (secret) was hidden in past ages from previous generations but was made known firstly to Paul, then to Christ’s holy apostles and prophets, and finally manifested to his saints ( see Rom. 16: 25, 26; Eph. 3: 3–9; Col. 1: 26).
Throughout Acts, the general theme is the Kingdom, not the Assembly. The Assembly is there but its present, final constitution is unwritten. At Pentecost, there was not a single Gentile in the Assembly—it was entirely Jewish. To apply the teaching of the prison epistles on its members in the time of the Acts only creates confusion.
The word assembly has a theological meaning now that it never had initially. The word is used by Stephen in Acts 7: 38 in relation to Israel (see Acts 7: 38) and means no more than a body of people called out from a general company. The Lord’s word “I will build my assembly” could have been fulfilled on the day of Pentecost when there were no Gentiles in the Assembly, for there is nothing in His statement to suggest the inclusion of Gentiles. We, with hindsight, can look back and allow the Lord’s word to run beyond Acts 2 to the present day as now knowing the truth of the one body, embracing Gentiles and Jews on the same ground (which is what we understand by the word assembly today). However, in Acts 2 there is no such thought. The Jews had crucified their King, and thus forfeited any right to the Kingdom on earth. Yet a message of grace is put to the nation through Peter (see Acts 2: 36–39) and later he adds the promise “Repent therefore and be converted ... and he may send Jesus Christ, who was foreordained for you ...” (Acts 3: 19–21). Those who responded in faith were “added” to the Assembly having been saved and separated, “from this perverse generation” (Acts 2: 40, 41). The final public testimony to the nation in Jerusalem was given by Stephen who saw the Lord as Son of Man (a title identified with the earth and the Kingdom) standing, ready to return and set up the Kingdom in power on earth.
Throughout the Acts the Jew has priority over the Gentile and accordingly Paul always went to the Jew first (see Acts 13; 14 etc.). At the end of the book Paul called to him “the chief of the Jews” (Acts 28: 17) in Rome. He told them “I have done nothing against the people or the customs of our forefathers”—an impossible statement if He had publicly ministered to Gentile and Jew as having equal status in one body. This shows that the ministry peculiar to the Assembly as the one body was not as yet part of the public testimony while there was still a possibility of repentance with Israel. The testimony was that of the Kingdom and not the Assembly. Hence I judge that because there was a possibility that Israel would repent and the Kingdom be established on earth, the Lord in His 40 days of resurrection ministry instructed the disciples about the Kingdom and not about the Assembly.