A.T. Robertson Commentary 1 Corinthians 13:6

"rejoiceth not in unrighteousness, but rejoiceth with the truth;" — 1 Corinthians 13:6 (ASV)

Rejoiceth not in unrighteousness (ου χαιρε). See Ro 1:32 for this depth of degradation. There are people as low as that whose real joy is in the triumph of evil.

But rejoiceth with the truth (συνχαιρε δε τη αληθεια). Associative instrumental case after συν- in composition. Truth personified as opposed to unrighteousness (2 Thessalonians 2:12; Romans 2:8). Love is on the side of the angels. Paul returns here to the positive side of the picture (verse 4) after the remarkable negatives.