A.T. Robertson Commentary 2 Corinthians 4:15

"For all things [are] for your sakes, that the grace, being multiplied through the many, may cause the thanksgiving to abound unto the glory of God." — 2 Corinthians 4:15 (ASV)

Being multiplied through the many (πλεονασασα δια των πλειονων). Late word πλεοναζω from πλεον, more, "making more through the more," with play on πλεον. One can think of Bunyan's Grace Abounding.