1 Kings 2:37 - Joseph Benson’s Commentary on the Old and New Testaments

In the day thou passest over the brook Kidron, &c. Which Solomon mentions, because it was in the way to Bahurim, where Shimei's former and settled habitation was, as appears by comparing 2 Samuel 15:23, with 1 Kings 16:5. But Solomon's meaning was, and so, no doubt, was understood by Shimei, that if he went out of Jerusalem any way, to a greater distance than Kidron was from thence, he should die for it; for when he went to Gath, after his servants, he went not over Kidron, but the direct contrary way, that city lying westward of Jerusalem, as Kidron did eastward. Thy blood shall be upon thine own head The blame and guilt of thy blood shall lie upon thyself only. In other words, his death should be owing to himself only, as the condition of his holding his life was known to him and accepted by him, as appears from the next verse.