"If you say, 'Behold, we did not know this,' does not he who weighs the heart perceive it? Does not he who keeps watch over your soul know it, and will he not repay man according to his work?"
"Ignorance of the law does not excuse" is that frequently cited principle of jurisprudence that tells us we cannot escape culpability for transgressing the law simply because we did not know what the law says on a particular point. Even though it is a principle of secular law, this idea is very much in keeping with Scripture. In Luke 12:47–48, we read of two servants, one who knew the master's will and did not do it and another who did not know his master's will and did not do it. Both servants were beaten. The one who did not know the master's will received a lighter beating, but the point is that he was still punished for his transgression. Knowledge of the law does not keep us from being guilty in Adam (Rom. 5:12–21), though it may have a mitigating effect on punishment.
If true ignorance of what is right does not get one off the hook for doing what is wrong, how much more does feigned ignorance make one guilty of transgression? Many people will lie about how well they knew what was required of them, and in some cases they will be excused. However, their being excused is only temporary, for even if we are able to deceive other people, we can never do so with the Lord. He always knows the true state of our souls and the extent to which we knew what we should have done even when we did not do it. And He will repay us accordingly even if no one on this earth does so. That is what we learn in Proverbs 24:12.
The immediate context of today's passage concerns our obligation to save those who are being led to the slaughter, which almost certainly refers to the demand that we come to the aid of those who are innocent and yet are wrongly accused. If we fail to come to their aid and then pretend not to know that we should have helped them, we will not escape divine judgment. God knows the truth, and He will not allow those who engage in such evil to go unpunished or undisciplined. Of course, we can apply this principle more broadly. The Lord's attribute of omniscience, which is beautifully laid out in Psalm 139, means that He is ever aware of what we are doing and even what we know or do not know. We can fool other finite creatures, but we can never fool our infinite Creator. Nothing can be hidden from Him, so we can never think that our excuses will sway Him. Therefore, it is always best to be honest with others and with the Lord, for even if we escape earthly retribution with our lies, He will never miss our sin.
Coram Deo
God's omniscience is a scary attribute for those who do not also know His grace. All too often, our sin goes unnoticed by others, but the Lord is always aware of it. Thankfully, however, if we are covered with the blood of Christ, we know that there is forgiveness even for the transgressions we commit in secret. We need only to confess and forsake our sins. Let us not try to hide sins from God, and let us never fail to repent when it is necessary to do so.