Exodus 12:38-48 CEB

38 A diverse crowd also went up with them along with a huge number of livestock, both flocks and herds.
39 They baked unleavened cakes from the dough they had brought out of Egypt. The dough didn't rise because they were driven out of Egypt and they couldn't wait. In fact, they didn't have time to prepare any food for themselves.
40 The length of time that the Israelites had lived in Egypt was four hundred thirty years.
41 At the end of four hundred thirty years, on that precise day, all the LORD's people in military formation left the land of Egypt.
42 For the LORD, that was a night of intent watching, to bring them out of the land of Egypt. For all Israelites in every generation, this same night is a time of intent watching to honor the LORD.

Instructions for observing Passover

43 The LORD said to Moses and Aaron: This is the regulation for the Passover. No foreigner may eat it.

References for Exodus 12:43

      44 However, any slave who has been bought may eat it after he's been circumcised.
      45 No temporary foreign resident or day laborer may eat it.
      46 It should be eaten in one house. You shouldn't take any of the meat outside the house, and you shouldn't break the bones.
      47 The whole Israelite community should observe it.
      48 If an immigrant who lives with you wants to observe the Passover to the LORD, then he and all his males should be circumcised. Then he may join in observing it. He should be regarded as a native of the land. But no uncircumcised person may eat it.