This phrase milk and honey
is used to describe the fruitfulness of the land (Deuteronomy 11:9–12). It is used first in Exodus 3:8 and then again in Numbers 14:8 and Deuteronomy 31:20. It became a common term for the Promised Land of Canaan. Most likely the term refers to date honey and goat's milk (not bee honey or cow's milk).1
6 For the people of Israel walked forty years in the wilderness, until all the nation, the men of war who came out of Egypt, perished, because they did not obey the voice of the LORD; the LORD swore to them that he would not let them see the land that the LORD had sworn to their fathers to give to us, a land flowing with milk and honey.