The sacrifice of the wicked is an abomination to the LORD: but the prayer of the upright is his delight.
– Proverbs 15:8
[T]his proverb deals with worship and our approach to God. It is consistent with the rest of Scripture in that worship is a matter of spirit and not outward form (1 Samuel 15:22). The word for sacrifice refers to the slaughter of an animal, and contextually to the purpose of offering to the Lord. It is a ritual act. Even if the outward act is performed impeccably, the wicked condition of the offerer’s heart makes it an abomination to God (Isaiah 1:10-15). The wicked despise God’s word and want to perform a ritual for acceptance, but God hates and rejects it (Proverbs 21:27; 28:9; Luke 6:46). The contrast is the delight, pleasure or acceptance, of the prayer of the upright (Proverbs 15:29; 1 Chronicles 29:17).