And God is able to make all grace abound to you, so that having all sufficiency in all things at all times, you may abound in every good work.  (2 Corinthians 9:8)

Paul is exhorting the faithful Achaians to respond as the Macedonians and give generously to brethren in Jerusalem.   He illustrates this by quoting from the psalter:

He has distributed freely, he has given to the poor;
    his righteousness endures for ever.  (Psalms 112:9)

Thus, the apostle asserts the concept of God’s sufficiency is an essential Biblical truth, not just for the doubting Corinthian.