interpretation of the name ישׁוּ runs: ימּח שׁמו וזכרו. This curse shall overtake the family of the υἱὸς τῆς ἀπωλείας. All the sins of his parents and ancestors shall remain indelible above before God the Judge, and here below the race, equally guilty, shall be rooted out even to its memory, i.e., to the last trace of it.
Verses 16-20
He whom he persecuted with a thirst for blood, was, apart from this, a great sufferer, bowed down and poor and נכאה לבב, of terrified, confounded heart. lxx κατανενυγμένον (Jerome, compunctum); but the stem-word is not נכא (נכה), root נך, but כּאה, Syriac bā‘ā’, cogn. כּהה, to cause to come near, to meet. The verb, and more especially in Niph., is proved to be Hebrew by Dan 11:30. Such an one who without anything else is of a terrified heart, inasmuch as he has been made to feel the wrath of God most keenly, this man has persecuted with a deadly hatred. He had experienced kindness (חסד) in a high degree, but he blotted out of his memory that which he had experienced, not for an instant imagining that he too on his part had to exercise חסד. The Poel מותת instead of המית points to the agonizing death (Isa 53:9, cf. Eze 28:10 מותי) to which he exposes God's anointed. The fate of the shedder of blood is not expressed after the manner of a wish in Psa 109:16-18, but in the historical form, as being the result that followed of inward necessity from the matter of fact of the course which he had himself determined upon. The verb בּוא seq. acc. signifies to surprise, suddenly attack any one, as in Isa 41:25. The three figures in Psa 109:18 are climactic: he has clothed himself in cursing, he has drunk it in like water (Job 15:16; Job 34:7), it has penetrated even to the marrow of his bones, like the oily preparations which are rubbed in and penetrate to the bones.n In Psa 109:19 the emphasis rests upon יעטּה and upon תּמיד. The summarizing Psa 109:20 is the close of a strophe. פּעלּה, an earned reward, here punishment incurred, is especially frequent in Isa 40:1, e.g., Psa 49:4; Psa 40:10; it also occurs once even in the Tôra, Lev 19:13. Those who answer the loving acts of the righteous with such malevolence in word and in deed commit a satanic sin for which there is no forgiveness. The curse is the fruit of their own choice and deed. Arnobius: Nota ex arbitrio
