Note 5 at Rom. 15:26: The account of Paul's travels in Acts do not give us any details about this collection for the poor saints Jerusalem. However, Paul does mention it as being the reason he made his last trip to Jerusalem (Acts 24:17) and he wrote about it in his letters to the Corinthians.

In 1 Corinthians 16:1-4, Paul gives instructions for the collection for the saints in Jerusalem. In verse 1, he says he gave the same instructions to the churches of Galatia. It is unclear whether he is saying he had also instructed the churches of Galatia to receive an offering for the Jerusalem saints or whether he was simply instructing the Corinthians to receive the collection in the same manner as the Galatians received their offerings. At any rate, Paul was only delivering the offerings from the churches of Macedonia and Achaia (this verse) during this trip to Jerusalem.

In 2 Corinthians 8:1-5, Paul spoke favorably about the attitude the churches of Macedonia (the churches of Thessalonica and Berea) had towards this offering. He acknowledged that the churches of Achaia (the Corinthian church) had purposed to send an offering a year before the Macedonian churches (2 Cor. 8:10; 9:2). Paul gave the impression that the offering from the Macedonian churches was unsolicited (2 Cor. 8:4).

Paul encouraged the Corinthians to participate generously in this offering reminding them that they would reap proportional to how they sow (2 Cor. 9:6). He stated clearly that they should not give under compulsion (2 Cor. 9:7) or try to give what they didn't have (2 Cor. 8:11-15). And he gave them a tremendous promise of God's physical blessing on them if they participated (2 Cor. 9:8-11).

This must have been a relatively large sum of money for Paul to be carrying to Jerusalem. Even though Paul could have demanded these people's trust since he was the apostle that brought them the gospel, he made provision for whoever they chose to accompany him to Jerusalem to make sure the money went for what it was intended (2 Cor. 8:20-21 with 1 Cor. 16:3).

This was a benevolence offering for the poor saints in Jerusalem.