John Gill Commentary Exodus 16:25

"And Moses said, Eat that to-day; for to-day is a sabbath unto Jehovah: to-day ye shall not find it in the field." — Exodus 16:25 (ASV)

And Moses said, eat that today
That is, he said this on the seventh day in the morning, and bid them eat of it whether baked or seethed, or as it was, or just as they pleased; however, they had liberty to eat of it, and indeed they had no other, because none fell on this day:

for today is a sabbath unto the Lord ;
a time of rest from labour, and to be employed in the service of the Lord:

today you shall not find it in the field :
should they seek for it, which they had no occasion to do, since there was a sufficiency provided the day before; and this he said to prevent their going out to seek for it, which, if out of curiosity or for any other reason any of them should do, it would be in vain and fruitless.