While sins of commission are often blatant and deliberate—transgressing a known law or command—sins of omission can be subtle and sneaky. We may not even realize that we have failed to do what God commands. While I might not ever commit adultery, for example, I could easily fail to love my wife as Christ loved the church (Eph. 5:25). In this example, committing adultery would be a sin of commission, while failing to love would be a sin of omission. When we consider and examine our own sins of omission, we should be humbled and flee any attempt to boast in self-righteousness.
The Westminster Shorter Catechism defines sin as “any lack of conformity to, or transgression of, the law of God” (WSC 14). Put simply, a sin of omission is any lack of conformity to God’s law, or failing to do what God commands, which is as grievous as actively transgressing what He commands. James writes, “So whoever knows the right thing to do and fails to do it, for him it is sin” (James 4:17). He also explains that we must not be only hearers of the Word, but doers also (1:22). While it is certainly true that we can sin without realizing it, sins of omission are intensified by knowledge. When we know what God has commanded us in His Word and we fail to do it, then we have silenced the voice of conscience and sinned against Him.
I want to suggest three ways we commit sins of omission—in our thoughts/desires, words, and deeds—and provide a gospel remedy. First, we commit sins of omission when we lack conformity to God’s law in our thoughts and desires—when we do not set our minds on things above (Col. 3:2) or when we fail to love God with all our hearts and minds (Luke 10:27). We are commanded to “take every thought captive to obey Christ” (2 Cor. 10:5) and to “rejoice in the Lord always” (Phil. 4:4). But how often are we doers of these commands? When we fail to honor God with our thoughts and desires, we commit sins of omission.