Why are even the prayers of the wicked an abomination to God (Proverbs 15:8, 29)?

Solomon presents an important and perhaps shocking contrast in Proverbs 15:8:
In this proverb, Solomon seems to be saying that even the sacrifices and prayers of the wicked are an abomination to God. Sacrifices are forms of prayer, and the prayers of the wicked are not acceptable to God. By contrast, the prayers of the upright are delightful to God. Proverbs 15:29 adds to the contrast:
The Lord is far from the wicked,
but he hears the prayer of the righteous.

We are reminded of what James says when he encourages his readers to draw near to God and God would draw near to them (James 4:8). James adds specificity to those instructions when, in the same verse, he exhorts readers to deal properly with sin: “Wash your hands, you sinners, and purify your hearts, you double-minded.” They couldn’t expect to have close fellowship with God if they were continually walking in sin.

God identified Israel as the people He chose. They were to bring their sacrifices, but as Proverbs 15:8 says, religious rituals are of no value to a wicked person. When the Israelites were steeped in sin, He told them to bring their worthless offerings no longer—their feasts had become burdensome to Him. He would hide His eyes from them, and though they multiplied their prayers to Him, He would not heed them (Isaiah 1:13–15). God’s people needed to be obedient to the covenant they had agreed to under Moses. Going through the motions would not help them, because “the sacrifice of the wicked is an abomination” (Proverbs 15:8, NKJV).

New Testament believers have a similar caution. Peter tells husbands, for example, that, if they are not living with their wives in a considerate and understanding way, then their prayers can be hindered (1 Peter 3:7). The bottom line is that the Bible doesn’t tell us that God always answers our prayers. In some instances, our prayers can be hindered by our own sin, even to the point that the prayers of the wicked are an abomination to God.

On the other hand, James explains that the prayer of a righteous person can be very effective (James 5:16). So, what makes a person righteous? In James 2:23, James quotes Genesis 15:6, reminding readers that Abraham was declared to be righteous by God when he believed in Yahweh (the preincarnate Jesus Christ, see John 8:56–59). Throughout his epistle, James challenges believers to put their faith into action. James shows that one can be righteous in position without being righteous in practice. The other apostles agree. Paul chastises the Corinthian believers for walking like infants or fleshly people (1 Corinthians 3:1). The husband who has his prayers hindered in 1 Peter 3:7 is a believer and righteous in his standing before God, but he is not righteous in how he walks with his wife. In each of these cases, the writers exhort readers that to have intimate fellowship with God, to have their prayers be effective, they need to be walking with Him, not just standing in Him.

Solomon equates being upright with pursuing righteousness (Proverbs 15:8–9). The prayers of the righteous are a delight to God (Proverbs 15:29). By contrast, the worship rituals of the wicked are an abomination to God. As the prophet Samuel put it, to obey is better than to sacrifice (1 Samuel 15:22). God has told us how we can be righteous both in our position (by faith) and in our practice (by walking in the Spirit). See John 3 and Galatians 5.

We cannot play games with God. He sees the heart, and even “the sacrifice of the wicked is an abomination to the Lord” (Proverbs 15:8, ESV). A pursuit of sin will affect our prayers and how God receives them.