Paul continues on his theme of giving in vv.15-20, and thinks back to the beginning of his gospel work (v.15, cf. Acts 16). Whether they helped with a lot or a little, Paul is thankful and will always remember (v.16). How true is that; whether people give us a lot or a little, help us a lot or a little, we always remember the good done to us.
Not so interested in the gift itself, Paul rather prefers to be thankful for the fruit that increases to [their] credit (v.17). As I read recently, we are never poorer for having given, and Paul is obviously pleased to help the Philippians see that their giving actually benefits both him and them.
Sent with Epaphroditus (v.18), Paul likens it to a fragrant offering, a sacrifice acceptable and pleasing to God. Our giving should, honestly, cost us something, and Paul harkens back to Old Testament times to show that modern day giving is, in principle, the same (Genesis 8.21, Exodus 29.18, 29.25, and 29.41).
Having commended the Philippians for their generosity (cf. 2 Corinthians 8), Paul turns to the bigger picture when he says that my God will supply every need of yours according to his riches in glory in Christ Jesus (v.19). There is no limit to his riches in glory in Christ Jesus, and Paul makes the connection that giving away earthly treasure in a sacrificial way is pleasing to God, and that God will then supply every need.
To live a life of radical trust like this might seem beyond us, it might make us feel anxious or nervous for the future because we are giving away what society tells us we need for the future, but here Paul promises the Philippians that my God will supply every need of yours according to his riches in glory in Christ Jesus (cf. Matthew 6.19-21, Luke 6.38). A life of radical trust in God’s provision is made a little easier when we consider what He has promised for our future.
Paul now wraps up the letter with a brief word of praise, a doxology, and writes to our God and Father be glory forever and ever. Amen (v.20). After the encouragement of mutual greetings (v.21), Paul reminds the readers that he is influentially incarcerated (v.22), and closes with this,
The grace of the Lord Jesus Christ be with your spirit. (v.23).
Paul began his letter with grace and peace (1.2), and ends his letter with the grace of the Lord Jesus Christ (4.23). This is a fitting end to a letter filled with joy despite tough earthly circumstances, filled with the encouragement and exhortation to rejoice despite what is going on around us, and a letter that teaches us that no matter our current earthly station or situation, that we have One to hold as more important and more precious, and that this One will empower and strengthen us to life a contented life of joy and peace when we trust Him.
Some Bibles have Amen at the end of v.23, and this is a fitting word of affirmation and agreement. So I read, Paul knew that what he had written was worthy to be agreed with, and we say, yes, Amen with the Philippians.