John Gill Commentary Romans 8:20

"For the creation was subjected to vanity, not of its own will, but by reason of him who subjected it, in hope" — Romans 8:20 (ASV)

For the creature was made subject to vanity
This designs the vanity and emptiness of the minds of the Gentiles, who were without God and Christ, and the Holy Spirit, without the law and Gospel, and grace of God.

It also designs the vain conceits they had of themselves, of their wisdom, knowledge, learning, and eloquence; likewise their vain philosophy, particularly their gross idolatry, their polytheism, or worshipping of many gods; together with their divers lusts and vices, to which they were addicted.

They were addicted to such a degree, that they might be truly said to be made subject thereunto, being under the government of these things, slaves unto them, and in such subjection, as that they could not deliver themselves from it; though it is said,

not willingly, but by reason of him who hath subjected the same in
hope .
Though they were willingly vain, yet they were not willingly made subject to vanity; they willingly went into idolatrous and other evil practices, but the devil made them subject, or slaves unto them; he led them captive at his will, and powerfully worked in them, by divine permission, so that they became vassals to him, and to their lusts.

For he seems to be designed, "by him who has subjected the same", and not Adam, by whom sin entered into the world.