These expressions, when spoken in Scripture with an eye to the Lord Jesus Christ, imply more than language can convey, or the imagination conceive. Jesus Christ, as the glorious Head of his body the church, is the fulness that filleth all in all. So the apostle speaks, Ephesians 1:23. And in the same Epistle he saith, speaking of Christ, "that he ascended up far above all heavens, that he might fill all things." (Ephesians 4:10) But when we have read those expressions, and pondered them to the utmost, What adequate conception have we of their meaning? So again, when it is said, that "in him dwelleth all the fulness of the GODHEAD bodily:" (Colossians 2:9) who shall undertake to say what that is? Not JEHOVAH dwelling in the God-man Christ Jesus, by filling that nature with grace and glory, as the Lord Jesus by his holy Spirit dwells in the saints, and fills their hearts, and unites himself to them, and they to him, by grace here, and glory above. Not thus; but the GODHEAD dwells in Christ Jesus, and fills that nature of Christ Jesus in a personal bodily union; as fire fills the iron substantially that is in it, so that it becomes itself fire from that union. Who shall go farther, and determine what this is?

And what endears all these precious views of our Lord in his fulness is, the interest his redeemed have in it. The apostle adds to this account of the GODHEAD in his fulness dwelling in Christ bodily, "and ye are complete in him." Here is the blessedness of the whole, as it concerns our happiness, and security, and glory in him. Hence the church is called "the glory of Christ." (2 Corinthians 8:23) And so the church is; for it is, indeed, Christ's glory, to give out of his fulness to his body the church, as the glorious Head of the church. And although his own personal glory is in himself, and to himself, in the GODHEAD, of his nature and essence, being"one with the Father, over all, God blessed for ever;"yet in his mediatorial glory, as the Head of his body the church, "of his fulness do all the members receive, and grace for grace." And it is the glory of the Lord Jesus to give out, and to make that body glorious like himself, and from himself, to be his glory for ever. Oh! the blessedness of thus beholding the fulness of the Lord Jesus. Oh! what encouragement to the faith of the Lord's poor, needy, empty people. In Jesus's fulness we are full; in Jesus's glory we are glorified; yea, it is Jesus's glory to receive me, to give out to me, and to be more glorious in thus receiving and giving. Hallelujah!

Bibliography Information
Hawker, Robert D.D. Entry for 'Fulness'. Hawker's Poor Man's Concordance and Dictionary. https://www.studylight.org/dictionaries/eng/pmd/f/fulness.html. London. 1828.

Bible Dictionaries Fulness

Hawker's Poor Man's Concordance And Dictionary

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Fulness