If God will forgive us for anything we do (no matter how bad it is), then why should we try to be good? It seems to me that all we have to do is ask God to forgive us when we do wrong, and that's the end of it. At least that's what some people say, don't they?
Yes, some people today do say this—just as some did in the first century. But the Bible says otherwise, and we must not make a mockery of God’s forgiveness and grace.
One reason we should avoid sin is because God wants us to love Him—and we cannot love God and at the same time love sin. The Bible’s message is clear: “If anyone loves the (sinful) world, the love of the Father is not in him” (1 John 2:15). Sin is an offense to God, and when we sin we are turning our backs on God and rejecting Him.
A second reason why the Bible commands us to avoid sin is because of what it cost God to make our forgiveness possible. Yes, for us forgiveness is a free gift; when we turn to Christ in repentance and faith, God promises to forgive us by His grace. But for God, forgiveness is costly because it cost Him the life of His own dear Son. On the cross, Jesus became the final and complete sacrifice for our sins, shedding His blood for us.
Don’t scorn what Christ did for you. Instead, turn from sin and by faith ask Christ to come into your life today. Then make it your goal to live for Christ, who “teaches us to say ‘No’ to ungodliness and worldly passions, and to live self-controlled, upright and godly lives in this present age” (Titus 2:12).