Charles Spurgeon Commentary 2 Kings 13:15-16

"And Elisha said unto him, Take bow and arrows; and he took unto him bow and arrows. And he said to the king of Israel, Put thy hand upon the bow; and he put his hand [upon it]. And Elisha laid his hands upon the king`s hands." — 2 Kings 13:15-16 (ASV)

Not because he could lend much strength, for he was an old man; but because this signified that God would be with the king, that the power which dwelt in the prophet's God would come through the prophet's hands to help the king.