εὐλογεῖτε τὸν κύριον πάντες οἱ ἄγγελοι αὐτοῦ δυνατοὶ ἰσχύι ποιοῦντες τὸν λόγον αὐτοῦ τοῦ ἀκοῦσαι τῆς φωνῆς τῶν λόγων αὐτοῦ (Psalm 103:20 LXX/OG)
"Bless the Lord, all ye his angels, mighty in strength, who perform his bidding, [ready] to hearken to the voice of his words." (Brenton LXX)
ὅπου ἄγγελοι ἰσχύϊ καὶ δυνάμει μείζονες ὄντες οὐ φέρουσιν κατ' αὐτῶν παρὰ Κυρίῳ βλάσφημον κρίσιν. (2 Peter 2:11 WH)
ἰσχύϊ is dative feminine singular; μείζονες is a comparative adjective that's nominative masculine plural.
οἱ ἄγγελοι are messengers (although ἄγγελοι is anarthrous in 2 Peter), but they clearly seem to be spirit creatures in this case. See 2 Kings 18:35.