John Calvin Commentary Acts 15:4

"And when they were come to Jerusalem, they were received of the church and the apostles and the elders, and they rehearsed all things that God had done with them." — Acts 15:4 (ASV)

They were received of the Church. By this word Church, he means the multitude itself and the whole body. After that, he assigns a special place to the apostles and elders, by whom Paul and Barnabas were particularly received.

Furthermore, because the apostles had no certain place of residence in Jerusalem, but went from time to time, sometimes to one place and sometimes to another, wherever occasion called them, that church had elders to whom the ordinary government of the Church was committed. We have previously declared how the one function differs from the other (Acts 14:23).

And by this it appears what brotherly courtesy there was in the apostles and elders, because they not only courteously received Paul and Barnabas, but as soon as they heard what success they had with the efforts they undertook, they magnified the grace of God.

Luke repeats again that form of speech which we had before in the preceding chapter, when he says that they declared whatever things God had done with them. In this, we must remember what I said before: that God is not made a fellow-laborer, but all the praise for the work is ascribed to Him.

Therefore, it is said that He did that with Paul and Barnabas which He did by them, just as He is said to deal mercifully with us when He helps our miseries.