This verse is variously explained, at least the second clause. Some render it, “His indignation, and not what is right;” then they add by itself, “his lies;” and lastly, “they have not done rightly,” or as others, “they will not do anything fixed,” which is more suitable, and comes near to the rendering which I have given. But I will not here discuss other interpretations, or try at large to disprove-them, but it is sufficient for us to understand the real meaning of the Prophet.

In the first place, God is here introduced as saying, I know his insolence The pronoun אני, ani, is emphatical, for in the last verse the Prophet had said, that the boastings of Moab were a terror, as they spoke loudly of their own strength and defences. As then they thus with open mouths sounded forth their own praises, they filled all their neighbors with terror; hence the Prophet said, We have heard the pride of Moab Now God also on his part gives this answer, I know, he says, his insolence; as though he had said, “The Moabites do not thus boast, but that I am a witness; all these things ascend to my tribunal.”

He afterwards adds, still in the person of God, Not rectitude are his lies By the word עברתו, obertu, which some render, “his indignation,” the Prophet means, I think, insolence. It signifies properly excess, as it comes from עבר, ober, to pass over. The noun is indeed often taken to express indignation, because anger keeps within no limits, but is, as Horace says, a momentary madness. ¹⁵¹⁵     Ira furor brevis est — Epist. 2 ad Loll. But on account of what the passage seems to require, I render it insolence, and it is the most suitable word. And God having declared that the insolence of Moab was seen by him, mentions also his lies The word בדים, means branches of trees, and sometimes sons or children, they being members of the community; and hence some render it “sons” here, as though the Prophet had said, that after the Moabites had been cut off, there would be none remaining to continue their name in the world. As then there was to be no posterity to the Moabites, they think that בדים, badim here means sons or children. But this view cannot be admitted, because we shall hereafter see that there was to be some residue to the Moabites. We cannot then take בדים, badim, but as referring to their vain boastings, for they were nothing but lies.

But we must consider what Jeremiah says; the word כן, ken, means right; and I take the two words as being in apposition, “His lies are not right;” that is, there is no stability in his lies. For when an apposition is explained, one of the words is turned to an adjective, or a preposition is inserted: Not right then are his lies; that is, in his lies there is no rectitude, or in his lies there is no stability. But the rectitude of which the Prophet now speaks, refers not to justice or equity, but to stability; and that it has this meaning may be gathered from other places. Then he says, that the boastings which the Moabites indulged in were vain, because God would not establish what they thought, or as they commonly say, what they presumed.

And then he adds the reason; the particle כן, ken, is to be taken here adverbially; it is an adverb of likeness, “so,” or thus, they shall not so do; that is, as they had conceived in their minds. It is a confirmation of the last clause; for why was there to be no stability in their lies? because God would break down the Moabites, so that their counsels would be vain, without any effect. We now then perceive the meaning of the words. Isaiah 16:6 uses nearly the same expressions, but he does not add this confirmation, that they would not be able to do what they intended. He only says, “there shall no rectitude be in their boastings,” לא כן בדיו, la ken bediu, having previously spoken of the loftiness of their heart and of their ferocity and insolence; for he mentions the third word with the other two. ¹⁶¹⁶     The versions and the Targ. all differ as to this verse. The Vulg. is the best; it takes בדים, branches, and also limbs, in a metaphorical sense, signifying strength. I give the following rendering, —
   30. I know, saith Jehovah, his excess, (i.e. of pride;) But not so his strength, not so have they done.
   The mixture of numbers, singular and plural, is common in the prophets — “his” and “they.” The meaning seems to be, that however excessive was the pride and insolence of Moab, they had no power fully to effect their purposes. - Ed.

Now this verse may be accommodated to our use; whenever the ungodly indulge in boasting, and insolently arrogate all things to themselves, let us not fear and tremble, but bear in mind what the Prophet teaches us here, whose admonition is very necessary; for he shews that this pride is in derision with God, and that when the ungodly fulminate in a terrible manner, there will be no effect to their lies. It follows, —