ROM the cradle to the grave... and even beyond (Psalm 71:20), God is our resting place (Hebrews 4:10). It is the nature of faith that we rest in God; relying upon His strength and not upon our own strength. David made it his habit to seek after God constantly. He described God as his "habitation, whereunto," he said, "I... continually resort'' (Psalm 71:3). Sometimes we think of resorting as something which we do last. Someone might resort to violence after exhausting all other perceivable options (for example) in self-defense. Sadly, some of us only resort to praying when we are at the very end of our rope. But David continually resorted to God. Why not! Resort first, not last. Why try weaker options when we have a foolproof and time-tested solution (Psalm 71:19). David trusted in God and had been doing so habitually from the time that he was very young (Psalm 71:1-6 & 17).
Now, David began to look somewhat wistfully at his coming "retirement." He rightly anticipated that someday his physical strength would be completely gone (1st Kings 1:1). So, in preparation for that day, he prayed for God's mercy upon him in his future... when he knew old age would prevail to weaken him (Psalm 71:9 & 18). He desired that he would be able to rest then in his favorite refuge and resort (Psalm 71:21). By his own admission, as long as he knew that God would be with him, he had a reason to look forward to the sunset of his journey. And, since he didn't know how long the sun would take to set on his life, he committed himself to praising God while there was time (Psalm 71:15).