7:10 For Moses said, Honour thy father and thy mother; and, Whoso curseth father or mother, let him die the death:
In this passage, Jesus is criticized by the Pharisees for not washing his hands before eating. He defends himself by attacking them for not killing disobedient children according to the commandment of God: "He that curseth father or mother, let him die the death."

The "commandment of God" that Jesus referred to is found in Leviticus 20:9.

For every one that curseth his father or his mother shall be surely put to death: he hath cursed his father or his mother; his blood shall be upon him.
And Jesus had a good point here. The Bible is clear about children -- those that curse their parents (Leviticus 20:9), or strike them (Exodus 21:15), or refuse to obey them (Deuteronomy 21:18-21) are to be killed, in the latter case by stoning to death. But the Bible is much less clear about washing hands before eating.

So don't worry too much about washing up before meals. There's not much in the Bible about it and Jesus didn't bother with it. But if you kids disobey you, you know what you have to do.