A.T. Robertson Commentary 2 Corinthians 9:15

"Thanks be to God for his unspeakable gift." — 2 Corinthians 9:15 (ASV)

Thanks be to God (χαρις τω θεω). Third time (verses 11,12,15).

For his unspeakable gift (επ τη ανεκδιηγητω αυτου δωρεα). One of Paul's gems flashed out after the somewhat tangled sentence (verses 10-14) like a gleam of light that clears the air. Words fail Paul to describe the gift of Christ to and for us. He may have coined this word as it is not found elsewhere except in ecclesiastical writers save as a variant (B L) for αδιηγητον in Aristeas 99 (θαυμασμον ανεκδιηγητον, "wonder beyond description," Moulton and Milligan's Vocabulary). See similar word in Ro 11:33 (ανεξιχνιαστα, unsearchable) and Eph 3:8.