Why is pride supposed to be a sin? I don't see what's wrong with taking pride in your work, or in your children, or things like that.
You’re right up to a point; it’s not necessarily wrong, for example, to take pride (or satisfaction) in a job well done. In fact, the Bible urges us to work hard so we’ll be satisfied with the results. It says, “The diligent man prizes his possessions” (Proverbs 12:27).
But even this kind of pride can become wrong — if we end up taking credit for what we’ve done instead of thanking God for helping us. In other words, the kind of pride the Bible condemns is a pride that puts ourselves first, and leaves God out of the picture. When that happens, we take credit for everything we accomplish, and we live only to please ourselves. This is why pride is at the root of almost every other sin.
Do you remember Jesus’ parable of the rich fool, who was wealthy in things but poor in soul? (You can read it in Luke 12:15-21.) He was proud of his wealth, and all he was concerned about was himself: “I’ll say to myself, ‘You have plenty of good things laid up for many years. Take life easy; eat, drink and be merry'” (Luke 12:19). But that night he died — and it was too late to turn to God. His pride became his downfall.
Don’t let this happen to you. Instead, realize that you are a sinner and need Christ, and then humbly turn to Him in repentance and faith. Then make it your goal to live for Christ every day. The Bible says, “God opposes the proud but gives grace to the humble” (1 Peter 5:5).