How could you forget?

Exodus 17:13-14

And Joshua discomfited Amalek and his people with the edge of the sword. And the Lord said unto Moses, Write this for a memorial in a book, and rehearse it in the ears of Joshua: for I will utterly put out the remembrance of Amalek from under heaven.

  So Joshua puts a huge whooping on Amalek, Moses' arms are like jello, and the victory was awesome. Why then the command to "rehearse it in the ears of Joshua"? Who's gonna forget this?
 
  Let me use myself as an example. I have watch God totally carry me through life's trials. His faithfulness is amazing. I have fought in the trenches, doubted if it would work, and God came through.

  Will I remember former victories when I fight future battles? Will I have those around me to strengthen me as Moses did?

  Then there is poor old Moses. He starts to tire, his arms come down, and his side starts losing! No pressure there! What if some ants started crawling up his leg and he just had to swat at them?! How uncomfortable.

  Then there is the uptight baptist who said, "Who is that crazy guy on the hill holding his hands up?! We are fighting here and he is holding some praise and worship service up there?  The heretic!"

  I should make this into a small play. The humor would be great.