Commenting on Colossians 1:18, “And he [Christ] is the head of the body, the church”, Thomas Manton writes:
[T]he church is the body. By the church is meant the church mystical, or all such as are called out of the world to be a peculiar people unto God. Now, these considered collectively or together, they are a body; but singly and separately, every believer is a member of that body: 1 Cor. 12:29, ‘Now ye are the body of Christ, and members in particular.’ All the parts and members joined together are a spiritual body, but the several persons are members of that body. Yea, though there be many particular churches, yet they are not many bodies, but one body, so it is said, 1 Cor. 12:12, ‘As the body is one, and hath many members, and all the members of that body, being many, are one body, so also is Christ.’ He is the head, and the many and divers members of the universal Christian church are but one body. The universal invisible church of real believers is one mystical body knit by faith to Christ, their head, and by love among themselves. And the visible universal church is one politic body, conjoined with Christ their head, and among themselves, by an external entering into covenant with God, and the serious profession of all saving truths. They have all the same king and head, the same laws—the word of God—the same sacraments of admission and nutrition, which visibly, at least, they subject themselves unto, and have a grant of the same common privileges in the gospel.
Thomas Manton collected works, volume 1, page 454, Christ’s Eternal Existence and Dignity of her Person, sermon v.