Be not children in mind (mē paidia ginesthe tais phresin). “Cease becoming children in your intellects,” as some of them evidently were. Cf. Heb 5:11-14 for a like complaint of intellectual dulness for being old babies.
In malice be ye babes (tēi kakiāi nēpiazete).
Be men (teleioi ginesthe). Keep on becoming adults in your minds. A noble and a needed command, pertinent today.