2 Corinthians 3:17
“Now the Spirit is the Lord.” This too is Lord, he says. And that you may know that he is speaking of the Paraclete, he added,
“And where the Spirit of the Lord is, there is liberty.”
For surely you will not assert, that he says, 'And where the Lord of the Lord is.' “Liberty,” he said, with reference to the former bondage. Then, that you may not think that he is speaking of a time to come, he says,
Source: Homilies on Second Corinthians (New Advent)