Adam Clarke on Habakkuk 2:14

For the earth shall be filled - This is a singular and important verse. It may be first applied to Babylon. God's power and providence shall be widely displayed in the destruction of this city and empire, in the humiliation of Nebuchadnezzar, Dan 4:37, and in the captivity and restoration of his people. See Newcome, and see Isa 11:9.

Secondly. It may be applied to the glorious days of the Messiah. The land of Judea should by his preaching, and that of his disciples, be filled with the knowledge of God. God's great design fully discovered, and the scheme of salvation amply explained.

Thirdly. It may be applied to the universal spread of the Gospel over the habitable globe; when the fullness of the Gentiles should be brought in, and the Jews gathered in with that fullness. The earth cannot perish till every continent, island, and inhabitant, is illuminated with the light of the Gospel.