Numbers 9:10-11

9:10 “Tell the Israelites, ‘If any of you or of your posterity become ceremonially defiled by touching a dead body, or are on a journey far away, then he may observe the Passover to the Lord. 9:11 They may observe it on the fourteenth day of the second month at twilight; they are to eat it with bread made without yeast and with bitter herbs.