Psalms 51:17 - Matthew Poole's English Annotations on the Holy Bible

The sacrifices: this is instead of or of more value than many sacrifices. Of God; which God in such cases as mine requires, and will accept; in which sense we read of the work of God, 1 Thessalonians 6:28. A broken and a contrite heart, i.e. a heart deeply afflicted and grieved for sin, humbled under the sense of God's displeasure, and earnestly seeking and willing to accept of reconciliation with God upon any terms. See Isaiah 57:15, Isaiah 61:1 66:2 Matthew 11:28. This is opposed to that hard or stony heart, of which we read so oft, which signifies a heart insensible of the burden of sin, stubborn and rebellious against God, imminent and incorrigible. Thou wilt not despise, i.e. thou dost highly approve; as such negative phrases oft signify, as hath been formerly proved.