The orders of the angels are not listed in the Bible but are referred to in scripture. Pseudo-Dionysius, a Christian philosopher of the late 5th century CE, drew on passages from the New Testament as well as other sources of knowledge to describe an angelic hierarchy in his book De Coelesti Hierarchia, ‘The Celestial Hierarchy’.
St Gregory the Great, 590 to 604, put the ‘choirs’ into a list in one of his homilies: “We know on the authority of Scripture that there are nine orders of angels, viz., Angels, Archangels, Virtues, Powers, Principalities, Dominations, Throne, Cherubim and Seraphim.”
The nine choirs are broken up into three hierarchies: the highest hierarchy (Seraphim, Cherubim and Thrones); the second (Dominions, Virtues, Powers); and the third (Principalities, Archangels and Angels).
The following is taken from an Aleteia video on Instagram, ‘What do Angels do in Heaven?’ and catholic.org.
The Seraphim—Fire
Seraph in Hebrew means ‘burning’. The six-winged Seraphim are the closest to God and burn with love for Him. They praise God, calling, “Holy Holy Holy is the Lord of Hosts”. Of their six wings, two cover their faces, two cover their feet and the other two are for flying.
The Cherubim—Fullness of Knowledge and Wisdom
The Cherubim, the second highest in the hierarchy, have the fullness of divine knowledge and wisdom. In the book of Genesis, they guard Eden and God’s throne. In the New Testament, they are alluded to as celestial attendants in the Apocalypse (Rev 4–6). Catholic tradition describes them as angels who have an intimate knowledge of God and continually praise Him.
Thrones—Seat of Exaltation
Thrones are angels who contemplate the power and judgements of God. God inhabits and rests in them as on a throne where He sits to pronounce His judgements. They are angels of pure Humility, Peace and Submission. The lower Choir of Angels need the Thrones to access God. Apostle Paul in Colossians 1:16 says, “For in Him all things were created: things in heaven and on earth, visible and invisible, whether thrones or powers or rulers or authorities; all things have been created through Him and for Him.”
Dominions/Dominations—Justice
Dominions/Dominations are angels driven by zeal for God’s Kingdom. They manage the tasks of lower angels so that God reigns supreme over all His creatures.
Virtues—Courage
Virtues enforce the divine order and ‘run’ the universe. They are God’s executors in the most difficult works and most extraordinary miracles. They are sometimes referred to as “the shining ones”. They govern all nature: seasons, stars, moon, sun. St Peter mentions the virtues in his first epistle (3:22), as does St Paul in his Letter to the Colossians (1:16). According to theologian and philosopher Dr Peter Kreeft, in his book Angels and Demons, “The virtues receive their orders from the dominations and ‘run’ the universe, so to speak, especially the heavenly bodies. (‘Virtue’ used to mean power, might, or energy)”.
Powers—Order, Harmony
Powers are watchmen: they fight evil spirits and keep them under control within the limits God has placed for them. These Warrior Angels are also known as ‘potentates’ and they also help people who are struggling with vices.
Principalities—Authority
Principalities are angels that watch over earthly principalities: cities, nations, and kingdoms. They are also known as ‘Princedoms’ or ‘Rules’. Pseudo-Dionysius describes them like this, “The name of the Celestial Principalities signifies their Godlike princeliness and authoritativeness in an Order which is holy and most fitting to the princely Powers.”
Archangels—Unity
Archangels are God’s ‘messengers’ par excellence and carry His messages to mankind. The only ones whose names are reported in the Bible are Michael, the head of the heavenly armies; Gabriel, the messenger of the Annunciation, and Rafael, the healer. Raphael is mentioned in the Book of Tobit, healing Tobit, and delivering Sarah from a demon. He also guided Tobias along his journey.
Angels—Revelation, messengers
Angels are entrusted with taking care of the souls of men and women. Every person has their own Guardian Angel. The Bible tells us, “[The Lord] will give His angels charge of you to protect you in all your ways” (Psalm 91:11).