In Exodus 10, urged by his servants, Pharaoh offers to let Moses and Aaron and the men of Israel go worship Yahweh in the wilderness. However Moses says that old and young alike, sons and daughters, flocks and herds must go and keep the feast (10:9). Pharaoh insists that only the men go, but Moses goes out from the presence of Pharaoh and the Lord orders him to strike the land with the eighth plague of locusts.
There are a couple interesting points to make. First, the feast to Yahweh must include the children. Later in the law, the requirement specifically stipulates that it is all the males who must present themselves before the Lord three times a year (Ex. 23:17, Dt. 16:16), but it seems (based on this) like it was nevertheless the norm (or ideal) for their families and children to attend with them.
Second, there is an interesting contrast with the observance of Jacob’s funeral in Genesis 50 where the text explicitly refers to “their little ones, their flocks, and their herds” that were “left in the land of Goshen.” (Gen. 50:7-6). One immediate implication is that a feast to Yahweh is not a funeral. Families and children are ordinarily part of feasts but not necessary for funerals.
Clearly, little ones were part of the celebration of Passover (Ex. 13:8ff), which I believe is the feast that they are asking to celebrate. But this suggests implications for the celebration of the New Covenant passover meal, the Lord’s Supper. Just on the surface, one implication would be that the presence or absence of children at the Lord’s Supper is the difference between a feast and a funeral.
And, ironically for the Egyptians, it is the feast in which the children participate that becomes the means by which the Angel of Death strikes the firstborn sons of Egypt. When the children feast, the enemy is struck down.