Now the Lord is that Spirit: and where the Spirit of the Lord is, there is liberty. Now the Lord is that Spirit - In 2 Corinthians 3:6, 2 Corinthians 3:8, the word το πνευμα, spirit, evidently signifies the Gospel; so called because it points out the spiritual nature and meaning of the law; because it produces spiritual effects; and because it is especially the dispensation of the Spirit of God. Here Jesus Christ is represented as that Spirit, because he is the end of the law for justification to every one that believes; and because the residue of the Spirit is with him, and he is the dispenser of all its gifts, graces, and influences.
And where the Spirit of the Lord is - Wherever this Gospel is received, there the Spirit of the Lord is given; and wherever that Spirit lives and works, there is liberty, not only from Jewish bondage, but from the slavery of sin - from its power, its guilt, and its pollution. See John 8:33-36 (note), and the notes there.