Augustine of Hippo

"For truth is not in their mouth" (ver. 9). To whose judgment of course then there is no trusting, and therefore must we fly within to conscience, and the sight of God. "Their heart is vain." How then can truth be in their mouth, whose heart is deceived by sin, and the punishment of sin? Whence men are called back by that voice, "Wherefore do ye love vanity, and seek a lie?"

"Their throat is an open sepulchre." It may be referred to signify gluttony, for the sake of which men very often lie by flattery. And admirably has he said, "an open sepulchre:" for this gluttony is ever gaping with open mouth, not as sepulchres, which, on the reception of corpses, are closed up. This also may be understood hereby, that with lying and blind flattery men draw to themselves those whom they entice to sin; and as it were devour them, when they turn them to their own way of living. And when this happens to them, since by sin they die, those by whom they are led along, are rightly called open sepulchres: for themselves too are in a manner lifeless, being destitute of the life of truth; and they take in to themselves dead men, whom having slain by lying words and a vain heart, they turn unto themselves. "With their own tongues they dealt craftily:" that is, with evil tongues. For this seems to be signified, when he says "their own." For the evil have evil tongues, that is, they speak evil, when they speak craftily. To whom the Lord saith, "How can ye, being evil, speak good things?"