Acts 15:16
After this I will return, and will build again the tabernacle of David, which is fallen down; and I will build again the ruins thereof, and I will set it up: After this I will return, and will build again the tabernacle of David, which is fallen down; and I will build again the ruins thereof, and I will set it up:
Acts 15:16 belongs to James's testimony at the Jerusalem council that deliberated the place and admission of Gentile believers in the church. The question before that council was whether uncircumcised Gentiles should be granted admission to the church and whether they must be circumcised and keep the ceremonial law. In that setting the promise to return and rebuild David's fallen tabernacle and its ruins means God's work of accepting Gentiles who turn to Him alongside Israel. It means giving them a share in the privileges given to the Jews and a place in the Christian church rather than reserving salvation and the church's privileges for Jews alone.
The council decided that Gentile converts need not be circumcised nor observe the ceremonial law as a condition of belonging to Christ's church. That decision remained in force and was not a requirement for Gentile believers to observe the ceremonial law. At the council Paul related his conversion and the great work God had wrought through him among the Gentiles. The Spirit of the Lord witnessed to the word spoken, and the council, recognizing that God had favored the Gentiles with the Holy Spirit and seeking to follow the Spirit's guidance, yielded its prejudices, expressed harmony with Paul's position, and sent an address to the churches to that effect.
That council met years before Paul's later meeting with the brethren in the same city before the same assembly. Although some Jewish Christians resisted the change and remained attached to the customs and privileges of Judaism, the brief early difference over circumcision was soon settled. After the resurrection and ascension union had prevailed with believers of one heart and one mind. Through divine illumination and sanctification by the Spirit the settlement left believers perfectly joined in the same mind and judgment, believing and speaking the same things with peace and harmony, showing the unity that is and always will be the fruit borne under the influence of the Holy Spirit.