A month's provision, it seems, the host of Israel took with them out of Egypt, when they came thence on the 15th day of the first month, which, by the 15th day of the second month, was all spent.
Related Commentaries of Exodus 16:1
Exodus 16:1
1 And they took their journey from Elim, and all the congregation of the children of Israel came unto the wilderness of Sin, which is between Elim and Sinai, on the fifteenth day of the second month after their departing out of the land of Egypt.