Midrasch zu Schemuel II 18:14

The deeps were congealed (Exod. 15:8). He fashioned them into a kind of vault. In the heart of the sea (ibid.). Where is a man’s heart located? It is located just above two thirds of his height. Similarly, the water congealed over them at two thirds of its depth. The sea had no heart; a heart was attributed to it. A terebinth has no heart, but a heart was ascribed to it, as it is said: While he was yet alive in the heart of the terebinth (II Sam. 18:14). The heavens have no heart, but He attributed a heart to them, as it is said: And the mountain burned with fire unto the heart of heaven (Deut. 4:11). The sea, which had no heart, and to which He ascribed a heart, came and punished the Egyptians who possessed hearts, but who nevertheless had subjected Israel to all manner of afflictions. The terebinth has no heart, but the heart which was attributed to it, went and punished Absalom, who had a heart, for he had deceived three hearts: his father’s, the court’s, and that of the men of Israel. And the heaven which had no heart, but to which a heart was ascribed, came and sent down manna to Israel, which possessed a heart, accepted the Torah with all its heart, and loved its Creator with all its heart.

Rabbi Eliezer said: Come and see the integrity and perfection of that man, for he said to Joab, Even if thou wouldst give me gold and silver I would not transgress the king's commands which he commanded thee, as it is said, "And the man said unto Joab, Though I should receive a thousand (pieces of) silver in mine hand" (2 Sam. 18:12). Joab said to him: I beseech thee, show me the place where Absalom is hanging. But he did not consent. Joab began to bend the knee, and to prostrate himself before him, as it is said, "Then said Joab, Shall I not entreat thee in this wise?" (2 Sam. 18:14). Then he took (Joab) by his arm, and showed him the place where Absalom was hanging. Everyone who transgresses the commandment "Honour thy father" is accounted as though he had transgressed the Decalogue. Therefore was (Absalom) pierced by ten spears, as it is said, "And ten young men that bare Joab's armour compassed about and smote Absalom; and slew him" (2 Sam. 18:15).