The human mind is not compatible with worry! Worry messes with your mind. Worry is anxiety about things that you cannot control. This comes, in part, from believing you are alone in life. In response to this, Jesus tells you not to worry about even the most basic needs of life. He even tells you how to pray so that you will not worry.
In the Lord's Prayer, Jesus instructs you to ask God for your daily bread. By reading the verses that come after the Lord's prayer in Matthew 6, we see that Christ was talking about more than just asking God for bread. Three times (in verses 25, 28, and 31), Jesus commands that you not worry about your life, clothes or food. That is amazing! Remember, worry messes with your mind. When you worry, you can't think well.
Worry is different from faith. Faith is choosing the path of obedience and trusting God to honor you as you obey. For example, the Israelites thought they had reason to worry about the giant Goliath. "How can we defeat this human killing machine?" Surely, if there was ever a good reason to worry, Goliath would qualify.