16:1 Now concerning the collection. From 2 Cor. 8:1–4 and Rom. 15:25–27 it appears that one of the purposes of Paul’s third missionary journey was to raise an offering from the Gentiles for Jewish Christians in Judea who were in need, possibly as a result of persecution. Apparently, Paul had already told the Corinthians about this project in an earlier letter (5:9). They had asked for more information and perhaps expressed reservations about it (Introduction: Date and Occasion).
for the saints. See 1:2 note.