Romans 8:29–30:

For those God foreknew he also predestined to be conformed to the likeness of his Son, that he might be the firstborn among many brothers. And those he predestined, he also called; those he called, he also justified; those he justified, he also glorified. (NIV)

For those whom He foreknew, He also predestined to become conformed to the image of His Son, so that He would be the firstborn among many brethren; and these whom He predestined, He also called; and these whom He called, He also justified; and these whom He justified, He also glorified. (NASB)

For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren. Moreover whom he did predestinate, them he also called: and whom he called, them he also justified: and whom he justified, them he also glorified. (KJV)

Paul now provides more proof in addition to common testimony of Christians to the argument of Rom 8:28: “In all things God works for the good of those who love him, who have been called according to his purpose.”

The argument is in prosyllogistic form: “Those God foreknew, He also predestined to be conformed to the likeness of his Son; those He predestined to be conformed to the likeness of his Son, He also called; those He called, He also justified; those He justified, He also glorified; therefore, in all things God works for the good of those who have been called according to his purpose.”

It is understood that “those who have been called according to his purpose” (Rom 8:28) are the same ones who are referred to at the beginning of Rom 8:29. This is made clear by Rom 8:30, where Paul states that they are “called.”

“God’s purpose” (Rom 8:28) is also illustrated as the end of our “predestination”: “to be conformed to the likeness of his Son.” We are also given the purpose: “That Jesus might be the firstborn among many brothers/brethren.” That is to say, we can not be heirs to God with Jesus were we not children of God, as referenced in Rom 8:14–23, and so God does all things to conform us to the likeness of his Son that we may become part of His family and thus heirs to all that God will reveal when he comes again in glory.