He does not faint nor grow weary, and his knowledge is beyond all knowledge. But it is up to us to believe it. Or, as the verse says, put our hope in God. The strength God gives us is to help us do normal things, like running and walking through life, as well to do extraordinary things in times of crisis. Things we never thought we could do.
Life is tough.
People used to believe that if you were sick, or there was an earthquake, that it was a punishment from God. God simply built a world with physical laws designed in a specific way. We are also creatures of Free Will. Well, it can seem like chance, but everything responds to the laws of this world that God has created. God has to let us make what can be foolish choices.