Charles H. Spurgeon on Psalms 71:9

Cast me not off in the time of old age, etc. David, mindful of the noble actions which, through God's assistance, he had achieved in his youth, beseeches him not to desert his servant, when persecuted by a rebellious son, in his old age. The weakness and temptations peculiar to that time of life, render this a petition necessary for all to make, before we are overtaken by it. The church findeth but too much occasion to make the same, now that she is sunk in years; when faith languisheth, charity waxeth cold, and the infirmities of a spiritual old age are coming fast upon her. George Horne.