Matthew Henry on 2 Samuel 13:1-20
We have here a particular account of the abominable wickedness of Amnon in ravishing his sister, a subject not fit to be enlarged upon nor indeed to be mentioned without blushing, that ever any man should be so vile, especially that a son of David should be so. Amnon's character, we have reason to think, was bad in other things; if he had not forsaken God, he would never have been given up to these vile affections. Godly parents have often been afflicted with wicked children; grace does not run in the blood, but corruption does. We do not find that David's children imitated him in his devotion; but his false steps they trod in, and in those did much worse, and repented not. Parents know not…
Read the whole note in the consoleJamieson-Fausset-Brown on 2 Samuel 13:12
do not force me--The remonstrances and arguments of Tamar were so affecting and so strong, that had not Amnon been violently goaded on by the lustful passion of which he had become the slave, they must have prevailed with him to desist from his infamous purpose. In bidding him, however, "speak to the king, for he will not withhold me from thee," it is probable that she urged this as her last resource, saying anything she thought would please him, in order to escape for the present out of his hands.
Adam Clarke on 2 Samuel 13:13
Speak unto the king - So it appears that she thought that the king, her father, would give her to him as wife. This is another strong mark of indelicacy in those simple but barbarous times. There might have been some excuse for such connections under the patriarchal age, but there was none now. But perhaps she said this only to divert him from his iniquitous purpose, that she might get out of his hands.
John Gill on 2 Samuel 13:14
Howbeit, he would not hearken unto her voice,.... His lust was so inflamed and enraged, that he could not attend to any arguments, though ever so forcible, that were offered to him:
but being stronger than she, forced her, and lay with her; whether she cried out or not, as the law directs in such cases, Deuteronomy 22:25; is not said; she might, and nobody hear her and come to her assistance; or she might not choose to expose her brother to his servants.