Why is it important the Giver keep all the memories? Explain.

From the text:

He lay on the bed, aching. "Why do you and I have to hold these memories?"

"It gives us wisdom," The Giver replied. "Without wisdom I could not fulfill my function of advising the Committee of Elders when they call upon me."

In a seemingly perfect world, the Giver holds onto memories with which he can advise the elders.