John Gill Commentary 2 Corinthians 9:12

"For the ministration of this service not only filleth up the measure of the wants of the saints, but aboundeth also through many thanksgivings unto God;" — 2 Corinthians 9:12 (ASV)

For the administration of this service
Not only by the Corinthians, and others, in giving and collecting, but by the apostles in ministering and distributing their contributions to the poor saints, produced these two very good effects: for it

not only supplies the wants of the saints ;
makes up their deficiencies, relieves their necessities, and furnishes them with what is comfortable and refreshing to them under their many sorrowful circumstances, which is answering a very valuable end:

but is abundant also by many thanksgivings to God ;
it has over and above this excellency in it, or its excellent use is enhanced, and abundantly appears by this consideration; that many precious souls are sent hereby to the throne of grace to give thanks to God, who put it into the hearts of the apostles to move the churches on their behalf, and who wrought upon them so cheerfully and largely to contribute to their necessities.