Sacrifices were offered: After the Departure of Israel from Egypt
Source: TTT
Exodus 5:3, 17
“The God of the Hebrews has met with us,” they answered. “Please let us go on a three-day journey into the wilderness to sacrifice to the LORD our God, or He may strike us with plagues or with the sword.” / “You are slackers!” Pharaoh replied. “Slackers! That is why you keep saying, ‘Let us go and sacrifice to the LORD.’
Exodus 18:12
Then Moses’ father-in-law Jethro brought a burnt offering and sacrifices to God, and Aaron came with all the elders of Israel to eat bread with Moses’ father-in-law in the presence of God.
Exodus 24:5
Then he sent out some young men of Israel, and they offered burnt offerings and sacrificed young bulls as peace offerings to the LORD.