Ephesians 6:12 (BSB)

For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this world’s darkness, and against the spiritual forces of evil in the heavenly realms.

From Ephesians 6. Also in the ESV.

Commentary on Ephesians 6:12

• John Calvin (Reformed), Calvin's Commentaries on Ephesians 6:12: 12. For we wrestle “Πάλη is properly a gymnastic term; but the Apostle often unites military with agonistic metaphors; and here the agonistic is not less suitable than the military. So in a similar passage of Max. Tyr. Diss. Version 9, volume 1 page 79, ed.
• Matthew Henry (Presbyterian), Matthew Henry's Complete Commentary on Ephesians 6:10-18: Here is a general exhortation to constancy in our Christian course, and to encourage in our Christian warfare. Is not our life a warfare? It is so; for we struggle with the common calamities of human life. Is not our religion much more a warfare?
• John Gill (Reformed Baptist), Exposition of the Old and New Testaments on Ephesians 6:12: For we wrestle not against flesh and blood,.... The Syriac, Arabic, and Ethiopic versions, and some copies, read "you", instead of "we". This is a reason why saints should be strong in the Lord, and why they should put on the whole armour of God, and prepare for battle, since their enemies are such as here described: not "flesh and blood"; frail mortal men, such...
• Albert Barnes (Presbyterian), Barnes' New Testament Notes on Ephesians 6:12: Verse 12. For we wrestle. Gr., "The wrestling to us ;" or, "There is not to us a wrestling with flesh and blood." There is undoubtedly here an allusion to the ancient games of Greece, a part of the exercises in which consisted in wrestling. , and following.