Charles Ellicott Commentary 2 Corinthians 8:11

"But now complete the doing also; that as [there was] the readiness to will, so [there may be] the completion also out of your ability." — 2 Corinthians 8:11 (ASV)

Now therefore perform the doing.—Better, complete the doing: for “perform the doing” is, in the modern use of the word, open to the charge of tautology. All the English versions, however, have “perform.”

The three stages are distinctly marked out in St. Paul’s mind:

1. Willing the purpose to give; in this they had shown readiness.
2. Setting about the work of giving; this Titus had reported.
3. Completing the work; this he now urged upon them, so that it might answer to the beginning.