3 John 1:5

The adjective πιστός is either act., “believing” (cf. John 20:27), or passive, “worthy to be believed,” “trustworthy” (cf. 2 Timothy 2:2). It is passive here, and it is well explained by Œcumenius as equivalent to ἄξιον πιστοῦ ἀνδρός. The peculiarity is that, by a sort of hypallage, the adjective is transferred from the subjective to the objective. Transitive: “Thou makest whatever thou workest on the brethren a believing act, a work of faith”. It was not mere hospitality but a religious service. Westcott's rendering: “thou makest sure whatsoever thou doest” gives πιστόν an unexampled and indeed impossible meaning. ποιεῖς, aor. of habitual and constant hospitality; ἐργάσῃ, aor. of each particular act. καὶ τοῦτο, “and that to”; more commonly καὶ ταῦτα (cf. Hebrews 9:12).