Albert Barnes Commentary Habakkuk 2:14

"For the earth shall be filled with the knowledge of the glory of Jehovah, as the waters cover the sea." — Habakkuk 2:14 (ASV)

For the earth shall be filled with the knowledge of the glory of the Lord - Habakkuk modifies to a degree the words of Isaiah which he incorporates, indicating that the destruction of Babylon was only a stage toward the coming of those good things for which God taught His people to long, not their actual arrival.

All the world would then be full of the knowledge of the glory of the Lord—not yet, however, entirely of Himself.

Jerome comments: “When Babylon is overthrown, then the power of the Lord’s might will be known to all. So the whole earth will be filled with the glory of the Lord, as the waters cover the bottom of the sea. This is according to the letter.

But it is plain that the Devil also and antichrist, and the perverse teaching of heretics, built a city in blood—that is, their own Church—with the destruction of those whom they deceive...

But when they fail in the fire (either this fire which is felt, or are consumed in the fire of the devil their prince, or are burned up with the fire of which the Lord says, I came to send a fire upon the earth, and so are brought back from their former course, and repent), the whole earth will be filled with the glory of the Lord.

Then, at the preaching of the apostles, their sound shall go out into all the world, as waters covering the sea—that is, all the saltiness and bitterness of the world which Satan had rained down and the earth had drunk in, the waters of the Lord will cover, and cause the place of their ancient bitterness to disappear.”

Rupertus comments: “For the Spirit of the Lord filled the earth, and when He filled it, the earth was filled with the knowledge of the glory of the Lord, so that unlearned and ignorant men became wise and eloquent, and the earthly became heavenly. Indeed, those who were earth became heaven, knowing the glory of the Lord, declaring the glory of God, not in just any way, but as waters cover the sea. However great the waters must be that would cover the sea, or compared to which the sea would be nothing, far greater is the miracle when the abundance of heavenly wisdom, given to the simple, surpassed the sea—that is, the wisdom of all mankind.”

Since this verse (Isaiah 11:9) was already an accepted image of the spread of the gospel, it would naturally be understood to include this as well. More generally, however, it declares how, following all God’s judgments, a greater knowledge of Him would emerge. Cyril states: “All things are full of Christ, who is the Glory of the Father; for this reason He also said, I have glorified You on earth; I have finished the work which You gave Me to do (John 17:4).”