“Union with Christ is the greatest, most honourable, and glorious of all graces that we are made partakers of. It is called ‘glory,’ (2 Cor. 3:18).
The greatest humiliation of the Son of God consisted in His taking upon Him of our nature, (Heb. 2:8-9).
And this was ‘the grace of our Lord Jesus Christ, that, though He was rich,’—rich in the eternal glory, the glory that He had with the Father before the world was, (John 17:5), as being in Himself ‘God over all, blessed for ever,’ (Rom. 9:5),— ‘for our sakes He became poor,’ (2 Cor. 8:9), by taking on Him that nature which is poor in itself, infinitely distanced from Him, and exposed unto all misery.
All which our apostle fully expresseth, (Phil. 2:5–7), ‘Let this mind be in you, which was also in Christ Jesus: who, being in the form of God, thought it not robbery to be equal with God: but made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men.’
There was indeed great grace and condescension in all that He did and humbled Himself unto in that nature, as it follows in that place, ‘And being found in fashion as a man, He humbled Himself, and became obedient unto death, even the death of the cross,’ (Phil. 2:8).
But His assumption of the nature itself was that whereby most signally ἑαυτὸν ἐκένωσε, He ’emptied’ and ‘humbled Himself, and made Himself of no reputation.’
On this all that followed did ensue, and on this it did depend. From hence all His actings and sufferings in that nature received their dignity and efficacy.
All, I say, that Christ, as our mediator, did and underwent in our nature, had its worth, merit, use, and prevalency from His first condescension in taking our nature upon Him; for from thence it was that whatever He so did or suffered, it was the doing and suffering of the Son of God.
And, on the contrary, our grace of union with Christ, our participation of Him and His nature, is our highest exaltation, the greatest and most glorious grace that we can be made partakers of in this world.
He became poor for our sakes, by a participation of our nature, that we through His poverty may be rich in a participation of His, (2 Cor. 8:9). And this is that which gives worth and excellency unto all that we may be afterwards intrusted with.
The grace and privileges of believers are very great and excellent, but yet they are such as do belong unto them that are made partakers of Christ, such as are due to the quickening and adorning of all the members of His body; as all privileges of marriage, after marriage contracted, arise from and follow that contract.
For being once made co-heirs with Christ, we are made heirs of God, and have a right to the whole inheritance.
And, indeed, what greater glory or dignity can a poor sinner be exalted unto, than to be thus intimately and indissolubly united unto the Son of God, the perfection whereof is the glory which we hope and wait for, (John 17:22-23)?
Saith David, in an earthly, temporary concern, ‘What am I, and what is my father’s family, that I should be son-in-law unto the king, being a poor man, and lightly esteemed?’ (1 Samuel 18:23)
How much more may a sinner say, ‘What am I, poor, sinful dust and ashes, one that deserves to be lightly esteemed by the whole creation of God, that I should be thus united unto the Son of God, and thereby become His son by adoption!’
This is honour and glory unparalleled. And all the grace that ensues receives its worth, its dignity, and use from hence.
Therefore are the graces and the works of believers excellent, because they are the graces and works of them that are united unto.”