17 and if children, then heirs—heirs of God and joint heirs with Christ, if indeed we suffer with Him, that we may also be glorified together.
We inherit by grace the glory which is Jesus Christ’s by right.
And all Mine are Thine, and Thine are Mine; and I am glorified in them (John 17:10).
And the glory which Thou gavest me I have given them; that they may be one, even as We are one: I in them, and Thou in Me, that they may be made perfect in one; and that the world may know that Thou hast sent Me, and hast loved them, as Thou hast loved Me. Father, I will that they also, whom Thou hast given Me, be with Me where I am; that they may behold My glory, which Thou hast given Me: for Thou lovedst Me before the foundation of the world (John 17:22-24).
if so be = indication that suffering with Christ is characteristic of believers. This is not making our inheritance conditional.
glorified together — should be “glorified with Him.” We share Christ’s glory, not part belonging to each but all to both. Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ (Ephesians 1:3).
It is very important to note that this suffering is not voluntary suffering. This is not a suffering which we choose to undergo through surrender, or through living in such a way that we will draw upon ourselves the hatred of the world. This is the sympathetic suffering which comes because of the oneness which we have with all the body. If we have a hurt foot, we may have a headache from the pain of the foot. An infected organ of the body may cause the whole body to be listless or feverish.
This sympathetic suffering is what is in view in our text in Romans. If we — the whole body of Christ; all the believers of all ages — suffer with Him, we shall bear in mind that we are to be glorified together. When we are saved, we are called out of the world to be joined to the Savior. The moment we are thus joined to Him we become the objects of all the hatred which the unregenerate world has toward our Lord. — Barnhouse, page 119-120.