The Rulers and Authorities, to whom Paul and also Peter refer, are supernatural beings that oppose Christ.
Below are the references to Rulers and Authorities in the New Testament.
In the following it refers to earthly rulers:
“Remind the people to be subject to rulers and authorities, to be obedient…” (Titus 3:1-2)
In the following verses it may refer to earthly or heavenly rulers:
“For I am convinced that neither death nor life, neither angels nor demons, neither the present nor the future, nor any powers, neither height nor depth, nor anything else in all creation, will be able to separate us from the love of God that is in Christ Jesus our Lord“.
“by Him all things were created, both in the heavens and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things have been created through Him and for Him” (Col. 1:15).
But in most instances it seems clear that it refers to heavenly rulers; ranks of angelic beings, either faithful or fallen angelic beings::
“He (Christ) is the head over all rule and authority” (Col. 2:10) “… the cross. When He had disarmed the rulers and authorities, He made a public display of them, having triumphed over them through Him” (Col 2:15) (Col. 2:10-15 forms a unit, describing how Christians have been made complete “in Him” (2:10) by disarming the supernatural “rulers and authorities” through the Cross. For further information, please see the article Disarmed the rulers and authorities.
“Then the end will come, when he hands over the kingdom to God the Father after he has destroyed all dominion, authority and power” (1Cor. 15:24).
“… he raised him (Christ) from the dead and seated him at his right hand in the heavenly realms, far above all rule and authority, power and dominion“ (Eph. 1:19-21).
“His intent was that now, through the church, the manifold wisdom of God should be made known to the rulers and authorities in the heavenly realms …” (Eph. 3:10, 11)
“For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms” (Eph. 6:12).
“… Jesus Christ, who has gone into heaven and is at God’s right hand –with angels, authorities and powers in submission to him” (1Pet. 3:21, 22).
As the above indicates, the supernatural rulers and authorities are forces that oppose Christ. Our struggle is against them (Eph. 6:12), but they have been disarmed by the Cross (Col. 2:14-15). In the end they will be made to submit to Christ (1Pet. 3:21, 22) and be destroyed (1Cor. 15:24).