Because the LORD kept a vigil that night to bring them out of the land of Egypt, this same night is to be a vigil to the LORD, to be observed by all the Israelites for the generations to come.
42. It is a night to be much observed. He shows that the Israelites have good cause for sacrificing to God with a solemn ceremony year by year for ever, and for celebrating the memory of that night; and that the Passover was instituted in token of their gratitude.
Here is the departure of the children of Israel out of Egypt; having obtained their dismission, they set forward without delay, and did not defer to a more convenient season. Pharaoh was now in a good mind; but they had reason to think he would not long continue so, and therefore it was no time to linger. We have here an account, 1.
Commenting on Exodus 12:37-42
But every man's servant that is bought for money,.... And so his own property: when thou hast circumcised him; as such an one ought to be, according to the covenant of circumcision given to Abraham, Gen 17:13, though one should think not without his consent; wherefore care was to be taken to purchase such servants as would be willing to conform to that rite, and...