Albert Barnes Commentary Psalms 89:39

"Thou hast abhorred the covenant of thy servant: Thou hast profaned his crown [by casting it] to the ground." — Psalms 89:39 (ASV)

You have made void the covenant of your servant - You have dealt with him as if there were no such covenant, as if no such promise had been made to him. The word rendered “made void,” means to abhor, or reject.

You have profaned his crown, by casting it to the ground - literally, “You have profaned to the earth his crown;” that is, You have treated it as a polluted thing; a thing to be rejected and abhorred; a thing which one casts indignantly upon the ground.