Numbers 32:23 KJV
But if ye will not do so, behold, ye have sinned against the LORD: and be sure your sin will find you out.
There is no such thing as an overlooked sin. All sin is either,
· judged in Christ
· repented of and turned from
· not committed or
· punished in God's time
Moses was at first taken aback by the two and half tribes who requested they be given their possession outside of the Promised Land. Once having heard their case he agreed but only on the condition that they help the rest of Israel in the battle for Canaan. Moses knew he would not be there to insist they keep their word but he could give this warning, “if ye will not do so …be sure your sin will find you out.
No one gets away with sin. Though the one who issues the warning may not be around to say "I told you so" the warning and its truth stand true.
Your sin, and mine will “find you out.” The mercy of God may prevent it for a time and the grace of God in Christ will mitigate it for those who get saved, but no one gets away with sin.