Food that God gave miraculously to the Israelites in the Exodus, after the food they had brought with them out of Egypt had run out. In the Book of Exodus, the Israelites found it one morning after the dew had evaporated: “Upon the face of the wilderness there lay a small round thing, as small as the hoar frost on the ground.”
manna from heaven
An unexpected aid, advantage, or assistance, as in After all the criticism in the media, that favorable evaluation was like manna from heaven. This expression alludes to the food (manna) that miraculously appears to feed the Israelites on their journey from Egypt to the Promised Land (Exodus 16:15).