The chapter begins with some excellent advice on giving. "On the first day of the week each of you is to put aside and save whatever extra you earn . . ." I like the idea that every Sunday I can set aside what I am going to give to God and to give to help others. It helps to make this decision, to make it regular and to follow through.
The letter ends with the usually ending of one of Paul's letters. He reviews his plans (5-9) he remembers his friends and co workers (10-12). He offers some last bits of advice (13-14). And he concludes with encouragement for his fellow laborers and greetings to the people he happens to know in town. Verse 21 -- ", Paul write this greeting with my own hand" -- is a reminder to us that Paul is dictating the letter and likes to sign off in his own writing.