Matthew Poole and continuators on Revelation 14:5

5 And in their mouth was found no guile: for they are without fault before the throne of God .

Not that any liveth, and sinneth not against God, but it is to be understood comparatively; they are without Fault, in comparison of the rest of the World; they have not in them the Guile of Hypocrisie; they are sincere. Or, possibly by Guile, is here understood, a Lie. All Idolaters are Liers, Rom. 1.25. and Idols are called Lies, Ier. 16.19. Amos 2.4. Mr Mede expoundeth this Text by Zeph. 3.13. The words may either more generally signifie the Holiness of these Persons, in opposition to Profaneness and Hypocrisie: Or more particularly their Freedom and Purity from Antichristian Superstitions, and Idolatry.

Marginal references: Psal. 32.2.; Eph. 5.27.