2 Samuel 16; 2 Corinthians 9; Ezekiel 23; Psalms 70–71
old age. it is not something our generation likes to talk about very much, at least not in realistic categories. We talk about preparing for retirement, but only with the greatest reluctance do we prepare for infirmity and death. Very few talk about these matters openly and frankly—without, on the one hand, dwelling on them (which shows they are frightened by them), or, on the other hand, suppressing them (which again shows they are frightened by them).
It is much more responsible to learn how to age faithfully, to learn how to die well. This the psalmist wanted. “Do not cast me away when I am old; do not forsake me when my strength is gone.… Even when I am old and gray, do not forsake me, O God, till I declare your power to the next generation, your might to all who are to come” (Ps. 71:9, 18). From his youth, he knew, God had taught him (71:17). Now he prays against abandonment in old age.
At one level, the psalmist is primarily asking that God will protect him against outside attacks when he is too old and infirm to resist (71:10ff.). This would be a special concern if the author of this particular psalm is David or some other Davidic king. A nearby nation that would not dare attack Israel when David was forty might be emboldened when David was pushing seventy. Though most of us are not kings, it is right and good to ask God for special protection when we grow so elderly and infirm that it is easy for others to take advantage of us.
But David’s vision is more comprehensive than mere protection. He wants so to live in old age that he passes on his witness to the next generation. His aim is not to live comfortably in retirement, but to use his senior years “to declare your power to the next generation, your might to all who are to come.” That is a prayer eminently worth praying. Should not senior saints be praying for grace to pass on what they have learned to a new generation? Perhaps this will be one on one, or in small groups. Perhaps one of them will take under his or her wing some young Christian or abandoned waif. Perhaps some experienced prayer warrior will teach a young Christian leader how to pray. And when there is too little strength even for these things, we shall pray that God’s grace will so operate in our weakness that God will be glorified in us: perhaps we shall teach younger Christians how to persevere under suffering, how to trust in the midst of pain, and how to die in the grace of God.
 Carson, D. A. (1998). For the love of God: a daily companion for discovering the riches of God’s Word. (Vol. 2, p. 25). Wheaton, IL: Crossway Books.