Hebrews 4:3

For we who believe (that is, we who personally trust and confidently rely on God) enter that rest (so we have His inner peace now because we are confident in our salvation, and assured of His power), just as He has said.  

God never meant for us to create our answers to problems using worry and fear. Anxiety and fear never solved a problem or made the answer come sooner.  God meant for us to rest in peace by knowing His power to work on our behalf.   We are to find the answer in the word, pray and believe God for the answer.  Our rest comes from our confidence in God.