Verse 23. "Which is his body" - As he is head over all things, he is head to the Church; and this Church is considered as the body of which he is especially the head; and from him, as the head, the Church receives light, life, and intelligence.
"And is the fullness of him" - That in which he especially manifests his power, goodness, and truth; for though he fills all the world with his presence, yet he fills all the members of his mystical body with wisdom, goodness, truth, and holiness, in an especial manner. Some understand the fullness or plhrwma, here, as signifying the thing to be filled; so the Christian Church is to be filled by him, whose fullness fills all his members, with all spiritual gifts and graces. And this corresponds with what St. John says, John i. 16: And of his fullness have all we received, and grace for grace. And with what is said, Col. ii. 9, 10: Ye are complete in him; kai este en autw peplhrwmenoi? And ye are in him filled full; i.e. with gifts and grace.
How, in any other sense, the Church can be said to be the fullness of him who fills all in all, is difficult to say. However, as Jesus Christ is represented to be the head, and the Church, the body under that head, the individuals being so many members in that body; and as it requires a body and members to make a head complete; so it requires a Church, or general assembly of believers, to make up the body of Christ. When, therefore, the Jews and Gentiles are brought into this Church, the body may be said to be complete; and thus Christ has his visible fullness upon earth, and the Church may be said to be the fullness of him, &c. See ver. 10.