Charles Ellicott Commentary Psalms 41:11

"By this I know that thou delightest in me, Because mine enemy doth not triumph over me." — Psalms 41:11 (ASV)

By this I know. —Better, shall know. His restoration would be a sign of the Divine favour, and a pledge of his victory over his enemies.

Triumph. —Literally, shout; “sing a paean.”