Amos predicted the (second) advent of Messiah after "these things" (i.e, the Tribulation, Amos 9:8-10). Messiah would set up His kingdom on the earth and restore the nation Israel (during the Millennium) under which the Gentiles would seek the Lord. We should understand the "and" in Acts 15:17 in the sense of "even" (the epexegetical use of this conjunction). [source][source][source]
"A close examination of this passage [1] reveals that there is a progression of thought leading to James" conclusion. First, God visits the Gentiles, taking from them a people for His name. In other words, God has promised to bless the Gentiles as well as Israel, but each in his own order. The Gentile blessing is first. Second, Christ will return-after the outcalling of the people for His name. Third, as a result of the coming of the Lord, the tabernacle of David will be built again; that Isaiah , the kingdom will be established exactly as promised in the Davidic Covenant. Amos clearly declared that this rebuilding will be done "as it used to be" ( Amos 9:11); that Isaiah , the blessings will be earthly and national and will have nothing to do with the church. Fourth, the residue of men will seek the Lord; that Isaiah , all the Gentiles will be brought to a knowledge of the Lord after the kingdom is established. This same truth is taught in passages like Isaiah 2:2; Isaiah 11:10; Isaiah 40:5; and Isaiah 66:23." [2][source]
There have been three main interpretations of James" use of Amos" prophecy ( Amos 9:11-12). [3] Some interpreters believe James meant that the inclusion of Gentiles in the church fulfilled God"s promise through Amos. [4] These (generally amillennial) interpreters see the church as fulfilling God"s promises to Israel. This view seems to go beyond what Amos said since his prophecy concerns the tabernacle of David, which literally interpreted would involve Israel, not the church. Second, some interpreters believe James meant that God would include Gentiles when He fulfilled this promise to Israel in the future. [5] However there was no question among the Jews that God would bless the Gentiles through Israel in the future. The issue was whether He would do this apart from Judaism, and this interpretation contributes nothing to the solution of that problem. This view does not seem to go far enough. A third view is that James meant that the present inclusion of Gentiles in the church is consistent with God"s promise to Israel through Amos (cf. Romans 16:25; Ephesians 3:9). [6] The present salvation of Gentiles apart from Judaism does not contradict anything Amos said about future Gentile blessing. This seems to be the best interpretation. [source][source][source]
"In other words, James says, God is working out His own plan: Israel, His covenant people have been set aside nationally because of their rejection of the Messiah. God is now taking out a people, Jew and Gentile, to constitute the Church of God. When He completes this work, the Lord is coming back the second time. That will be the time of blessing for the whole world [7]." [8][source]
James added the quotation from Isaiah 45:21 in Acts 15:18 b probably to add authority to the Amos prophecy. [source][source][source]
"The thought that the church was the divinely intended replacement for the temple is probably to be seen in Acts 15:16-18." [9][source]
The typical non-dispensational understanding of this text is that James was saying that the messianic kingdom had come and Amos" prediction was completely fulfilled. Progressive dispensationalists believe he meant that the first stage of the messianic kingdom had come and that Amos" prediction was partially fulfilled. [10] Normative dispensationalists view the messianic kingdom as entirely future. They believe Amos was predicting the inclusion of Gentiles in God"s plan and that James was saying that the present situation was in harmony with God"s purpose. Thus the Amos prediction has yet to be fulfilled. Deciding between these options depends first on whether or not one believes the church replaces Israel in God"s plan. If it does, one will side with non-dispensationalists here. If one believes the church and Israel are distinct in the purpose of God, then one has to decide if there is better evidence that Jesus has begun to rule over David"s kingdom now (progressive dispensationalism) or not (normative dispensationalism). I believe the evidence points to the fact that David"s kingdom is an earthly kingdom and that Jesus will begin reigning over it when He returns to earth at His second coming. [11][source]
James would have quoted a version of the Old Testament text that would have been acceptable to his audience, which included strict Jews. His quotation from Amos differs from the Hebrew text in meaning and the Septuagint in form, but it is identical to the text of4QFlorilegium ( Acts 1:12), an Essene rendering. [12][source]