30] What about the remains of the lamb?   

Now with regard to the instruction to let nothing of it remain until morning (Exodus 12:10), the instruction was simply to burn that which was not eaten, or used, in order that there be no remains in the morning (cf. Exodus 34:25).

Consider the following: Once the meal was eaten, and everyone was satisfied, the families would have then naturally known what remained, that is what would remain until the morning (whether the morning be at 2:00 am or 6:00 am).

Knowing what would remain until the morning, if they left it on the table, the families would have simply burned “the remains,” for that is what they were commanded to do. They were not to let anything remain until the morning.

There was no direct command as to when to burn the remains; only that Israel was told they had to burn what would be there in the morning, if they let it stay until the morning.

It was right after they were done eating; they saw what would remain until the morning, if they let it sit on the table (which back then would have been a bad practice) over night.

There was no logic to let the remains sit on the table, or on the spit, for some 12 hours. Knowing that none of the meal was to remain until the morning, they burned it without delay, right after dinner.

Certainly, a fire would be burning in their houses as they were eating, the same fire that was used to cook the lambs. Having then set “the remains” afire, nothing would remain until the morning. They were then ready to leave at a moments notice, in haste, just as he Eternal commanded them to be ready to do.

Israel was told to be ready to go. Israel was told to eat in haste, to have their staffs in hand, and their clothes on their back. In a common vernacular, they were told, do not go to bed this night; get ready to get out of town and do not let my Passover sacrifice remain on the table until the morning.

Israel left Egypt in haste (Deuteronomy 16:3; Exodus 12:33), they were thrust out. After they ate their meal, they heard the world outside their doors falling apart and they were thrust out (Exodus 11:1; Exodus 12:39). They began their exit, their exodus that night.

Once done eating, they burnt the remains and did not let anything remain until the morning.