Enjoy prosperity while you can. But when hard times strike, realize that both come from God. That way you will realize that nothing is certain in this life. (Ecclesiastes 7:14 NLT)
You can be a hero one day and a zero the next day, a millionaire one day and bankrupt the next. No matter how much you make, no matter how much you save, finances are uncertain.
So we worry. What does the Bible say about worry and money?
1. It’s unreasonable. (Matthew 6:25) You're going to have fears in life, but there are better things to be scared of than a lack of finances. Life is more than just the accumulation of things. Even if you go bankrupt, it could get worse. Worry about what’s truly important.
2. It’s unnatural. (Matthew 6:26) Jesus reminds us that animals and plants don’t worry. Birds don’t say, "I'd better build a bigger nest for retirement." Only human beings don't trust God to provide for them. Everything else in creation does.
3. It’s unnecessary. (Matthew 6:30) Financial fears come from a misunderstanding about God and what He's promised to do for you. He's assumed responsibility for your needs. He says, "I'm your Heavenly Father; I'm going to take care of your needs. You're my child." We always get into trouble when we doubt the love of God.
Worry is playing God. It's assuming responsibility for something that God has said He will take care of. Paul reminds us in Philippians 4:19, “And this same God who takes care of me will supply all your needs from his glorious riches, which have been given to us in Christ Jesus.”
God knows what's going on in your life — and in your wallet. God knows all your needs even before you ask. He wants to help you out.
Source: http://rickwarren.org/devotional/english/don-t-worry-trust-god