It is not our promises to the Lord but his promises to us that will give us victory over sin.
– Warren Wiersbe
God promises that sin will not have dominion over us if we are in Christ (Rom. 6:14). However, just because we make promises to “never do that again” or “never say this again” doesn’t mean we’ll be perfectly obedient. How many of us have made a promise to not do something ever again, yet five minutes later find ourselves doing the same thing or a relative of it?
Remember, Christ has already conquered sin and has power over it. We are called to have faith in him so we can kill sin by the power of the Spirit (Rom. 8:12-13). This happens by his grace, not our feeble, carnal promises to be better people. We kill sin to see Jesus more clearly, to be more like him. The goal is Christ — not a good, moral life.