Even though the fig trees are all destroyed, and there is neither blossom left nor fruit; though the olive crops all fail, and the fields lie barren; even if the flocks die in the fields and the cattle barns are empty, yet I will rejoice in the Lord; I will be happy in the God of my salvation. The Lord God is my strength; he will give me the speed of a deer and bring me safely over the mountains.
Habakkuk 3:17-19 TLB
When we rely upon our own strength, we can expect the supply to diminish with time. Our most devoted attempts to maintain our physical prowess will not win our battle against aging. We die daily. That's what getting older is all about. If we are blessed to live long lives, we will look up one day to find our youth is gone. This is one of the reasons God promises to always be our strength. When we finally come to the end of thinking we have ultimate control of our lives, which we had nothing to do with creating, we must then realize that our only hope is in God. He sent His Son, Jesus, to offer us eternal life because He planned for this life to end. Throughout our existence on this planet, it is He who is our strength and it will always be Him who brings us safely over every mountain into His Kingdom which has no end.