And Absalom met the servants of David. And Absalom rode upon a mule, and the mule went under the thick boughs of a great oak, and his head caught fast in the oak, and he was left hanging between the heaven and the earth; and the mule that was under him went away.
Read Chapter 18
When Absalom was cruelly attacking his father David, the speed of his mule caused him to collide with a thick oak tree, and the branches wound round his neck so that he was suspended high in the air. This was a prefiguration of the Lord’s betrayer. Just as Judas ended his life in the knot of a noose, so also David’s persecutor breathed his last through the pressure on his throat. - "Exposition of the Psalms 3.1"