Thou desirest not sacrifice; which is not to be understood absolutely, and universally, as appears from Psalms 51:19, but comparatively, of which See Poole on "Psalms 40:6", and with particular respect to David's crimes of murder and adultery, which were not to be expiated by any sacrifice, but by the law of God were to be punished with death. Thou requirest more and better sacrifices, which here follow. Else would I give it; else I should have spared no cost in that kind.
Related Commentaries of Psalms 51:16
Psalms 51:16
16 For thou desirest not sacrifice; else would I give it: thou delightest not in burnt offering.