Joint heirs — That we may know it is a great inheritance which God will give us for he hath given a great one to his Son. If we suffer with him — Willingly and cheerfully, for righteousness' sake. This is a new proposition, referring to what follows.
Related Commentaries of Romans 8:17
Romans 8:17
17 And if children, then heirs; heirs of God, and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together.