David was a youth when he defeated Goliath (1 Sam. 17:33). Jeremiah was a youth when he was called to be a prophet (Jer. 1:6). Timothy was a youth when Paul left him to care for the church at Ephesus (1 Tim. 4:12). We are never too young to serve the Lord.
Moses was 80 and Aaron 82 when they were called to lead the people out of Egypt (Ex. 7:7). Caleb was 85 when he conquered Hebron (Josh. 14:10). Anna was at least 84 when she told everyone about the birth of Jesus (Luke 2:36ff). We are never too old to serve the Lord.
“Remember also your Creator in the days of your youth, before the evil days come and the years draw near of which you will say, ‘I have no pleasure in them’” (Ecc. 12:1).
“So even to old age and gray hairs, O God, do not forsake me, until I proclaim your might to another generation, your power to all those to come” (Psa. 71:18).
Thayer Salisbury (condensed)
Via Broadway church of Christ