A.T. Robertson Commentary Romans 16:18

"For they that are such serve not our Lord Christ, but their own belly; and by their smooth and fair speech they beguile the hearts of the innocent." — Romans 16:18 (ASV)

But their own belly (αλλα τη εαυτων κοιλια). Dative case after δουλευουσιν. A blunt phrase like the same picture in Php 3:19 "whose god is the belly," more truth than caricature in some cases.

By their smooth and fair speech (δια της χρηστολογιας κα ευλογιας). Two compounds of λογος (speech), the first (from χρηστος and λογος) is very rare (here only in N.T.), the second is very common (ευ and λογος).

Beguile (εξαπατωσιν). Present active indicative of the double compound verb εξαπαταω (see 2 Thessalonians 2:3; 1 Corinthians 3:18).

Of the innocent (των ακακων). Old adjective (α privative and κακος), without evil or guile, in N.T. only here and Heb 7:26 (of Christ).