The document discusses the command given by God to Moses regarding the observance of the Passover in the wilderness of Sinai, one year after the Israelites' exodus from Egypt. It emphasizes the importance of maintaining the Passover ritual and provides rules for participation, particularly for those who were ceremonially unclean at the time. The text also reflects on the historical context of the ordinance and the necessity of diligent observance to prevent forgetfulness among the Israelites.