Read Exodus 13-15 at Bible Gateway
Exodus 13
The Israelites were given two ordinances in this chapter. The first born males of men as well as the first born males of animals were to be sanctified or “set apart” for the LORD. They had to first give them to the Lord and then redeem them for a price. This needed to be done so that the Israelites would be reminded that God saved their first born males in Egypt when all the first born males of the Egyptians had died.
God also instituted the feast of the unleavened bread. This feast started with the passover and lasted a week during which time they had to put away leaven or yeast from their houses and eat bread baked without leaven. The significance of not using leaven in the bread is made clear by emphasizing that they should be completely free of leaven in their homes. Leaven is a picture of sin throughout the Bible and we similarly should put away sin from our lives.