Charles Ellicott Commentary Exodus 16:15

"And when the children of Israel saw it, they said one to another, What is it? For they knew not what it was. And Moses said unto them, It is the bread which Jehovah hath given you to eat." — Exodus 16:15 (ASV)

It is manna. —This is certainly a wrong translation. The words of the original, man hu, must either be rendered, as in the Septuagint and the Vulgate, “What is this?” Or, as by Kimchi, Knobel, Gesenius, Kurtz, and others, “This is a gift.” It is against the former rendering that man does not mean “what” in Hebrew, but only in Chaldee, and that “what is this” would be a very strange name to give to a substance. Against the latter it may be said that neither is man found elsewhere in Hebrew in the sense of “a gift;” but it has that sense in Arabic, and in Hebrew manan is “to give.”

This is the bread — i.e., the promised bread. (See Exodus 16:4.)