2 Samuel 13:2 - Coke's Commentary on the Holy Bible

Amnon was so vexed, that he fell sick— It is natural to think, that the passion of love is nowhere so wasting and vexatious as where it is unlawful. A quick sense of guilt, especially where it is enormous, as in the present instance, strikes the soul with horror; and the impossibility of an innocent gratification loads that horror with desperation. Witness the two most remarkable instances of this kind found in history; that of Antiochus for Stratonice his mother-in-law, and this of Amnon for Tamar his sister. Indeed, that of Antiochus appears the less criminal of the two, inasmuch as he seemed determined to conceal his till death, and at the same time to hasten that death to prevent its publication, had not the sagacity of his physician discovered it. Though possibly Amnon had done the same, had not the importunity of his false and subtle friend Jonadab the son of Shimeah, David's brother, drawn the secret from him. It is lamentable to think, that the heirs of royalty, whose virtue is of infinitely more consequence than that of meaner men, should yet be under more temptations to taint it, from the poison of infectious flatterers.