35 Moreover what is written “You will destroy all that speak leasing:” one says that no lie is here excepted, but all condemned. Another says: Yea verily: but they who speak leasing from the heart, as we disputed above; for that man speaks truth in his heart, who hates the necessity of lying, which he understands as a penalty of the moral life. Another says: All indeed will God destroy who speak leasing, but not all leasing: for there is some leasing which the Prophet was at that time insinuating, in which none is spared; that is, if refusing to confess each one his sins, he defend them rather, and will not do penance, so that not content to work iniquity, he must needs wish to be thought just, and succumb not to the medicine of confession: as the very distinction of the words may seem to intimate no other, “You hate all that work iniquity;” but will not destroy them if upon repenting they speak the truth in confession, that by doing that truth they may come to the light; as is said in the Gospel according to John, “But be that does truth comes unto the light. You will destroy all who” not only work what You hate, but also “speak leasing;” in holding out before them false righteousness, and not confessing their sins in penitence.
Source: On Lying (New Advent)