Perhaps Jacob was alluding to Jeremiah 15:18 at this point: “Why is my pain perpetual, and my wound incurable, which refuseth to be healed? wilt thou be altogether unto me as a liar, and as waters that fail?” Jeremiah, unlike Jacob, does not condemn the liar to hell, but he certainly rebukes the liar “as waters that fail,” a serious matter to a desert culture.
Jacob may also be alluding to the Ten Commandments with their injunction against bearing false witness (Ex. 20:16), a reading that is strengthened by the fact that the next three verses also allude to the Decalogue. Jacob is not speaking simply about those who tell small “social” falsehoods. Rather, he more likely echoes Jeremiah’s condemnation of the liar. The liar, who also deceives himself or herself, has no power to nourish in a sustaining way. Those who promise to live according to the commandments, but do not, receive no benefit from the promise. The benefits of the gospel come not from making the promise, but living it.