LOVE expressed by 2 four year olds

This memory has always been a favorite conversation with my oldest son:

As my son turned four years old, I was concerned that he was accumulating too many material gifts. I wanted him to enjoy what he was given, but I also wanted to teach him what was most important. After turning the lights out one evening, I asked him, “William, do you know what the most important gift of all is?”

Without a hesitation he stunned me, “Love," he said. I was very proud of him as we cuddled. He thought about my question a little more and then said, “Mom, breastfeeding is love,” and he nursed to sleep.

I was reminded of it this morning. My youngest son who is four expressed his love through a knock-knock joke.

David: Knock-knock
Mom: Who's there?
David: David
Mom: David who?
David: David who loves you!