The Bible presents God as the source of all things, yet surprisingly, many people still struggle to trust God to supply for their needs. Anxiety, past troubles, concern for the future, and selfishness are all excuses that we put forth, but at the basis of all these, there is a lack of faith in God.
In response to this problem, Jesus teaches us to pray. As we commit our lives and our needs to God, He removes our anxiety and our distrust. He does this by revealing His faithfulness.
If you battle with fear or doubt, ask God to help you commit your life to Him and help you to trust Him fully. He is a faithful Father.