The Passover commemorated God’s deliverance of Israel from slavery in Egypt (see Exodus 12:1–28). This festival was meant to be celebrated on the fourteenth day of the month (Exodus 12:6) after the lamb had been set aside on the tenth day of the month (Exodus 12:3). The mention of both these dates in Joshua (Joshua 4:19; Joshua 5:10) emphasizes that Israel sought to do everything as they were commanded.
10 While the people of Israel were encamped at Gilgal, they kept the Passover on the fourteenth day of the month in the evening on the plains of Jericho.