David Aune on ἠγορασμένοι (Revelation 14:3)

The substantival ptcp. οἱ ἠγορασμένοι (masc. nom. pl. pf. pass.), “those who have been redeemed,” is a solecism because it is a masc. nom. pl. in apposition to αἱ ἑκατὸν τεσσεράκοντα τέσσαρες χιλιάδες, “the 144,000,” a fem. nom. pl. The same solecism occurs in 7: 4, χιλιᾶδες ἐσφραγισμένοι. οἱ ἠγορασμένοι emphasizes the resulting state of the subjects rather than the action that produced the condition (Fanning, Verbal Aspect, 160).

Aune, Dr. David. Revelation 6-16, Volume 52B (Word Biblical Commentary) (p. 903). Zondervan Academic. Kindle Edition.