Albert Barnes Commentary Psalms 50:17

"Seeing thou hatest instruction, And castest my words behind thee?" — Psalms 50:17 (ASV)

Seeing you hate instruction - That is, he is unwilling himself to be taught. He will not learn the true nature of religion, and yet he presumes to instruct others. Compare the notes on Romans 2:21.

And cast my words behind you - He treated them with contempt, or as unworthy of attention. He did not regard them as worthy of being “retained,” but threw them contemptuously away.