12 This service that you perform is not only supplying the needs of the Lord’s people but is also overflowing in many expressions of thanks to God.

Read 2 Corinthians 9:12 Using Other Translations

For the administration of this service not only supplieth the want of the saints, but is abundant also by many thanksgivings unto God;
For the ministry of this service is not only supplying the needs of the saints but is also overflowing in many thanksgivings to God.
So two good things will result from this ministry of giving—the needs of the believers in Jerusalem will be met, and they will joyfully express their thanks to God.