When we are young we are invincible, unstoppable and foolishly ignorant of our mortality. But we also were full of undying faith and knew the joy of being children of god. As we grew older we had to face our mortality and the fact we are not the unstoppable or unmovable force we once believed. We begin to lose faith in this world and in our selves, and many lose their faith in God as well.
We can reestablish our faith in God and we can also leave the fear of our mortality behind us with such faith. We must constantly remind ourselves where our strength, blessings and wisdom comes from, not from ourselves but from God. We must learn to let go and let God take control, the Ego or Self tends to be resistant to letting God be the one to be in control.
Fear is the enemy, it causes doubt and drains the power of faith, love and it keeps us from happiness. Selfishness is an enemy as well, one can not serve ones self before serving God nor can they truly help others is they seek to satisfy themselves first. We can only serve one master at a time, and if that master is our own self we tend to neglect not only God but all the people who need us and love us as well.
No one can serve two masters. Either you will hate the one and love the other, or you will be devoted to the one and despise the other. You cannot serve both God and money.
2 Timothy 1:7
For God hath not given us the spirit of fear; but of power, and of love, and of a sound mind.
Knowing this, that the trying of your faith worketh patience.