2 Samuel 23:13

three of the thirty chief Not the three mentioned before, but in all probability Abishai, Benaiah, and a third not named, who were promoted from the "Thirty" to form a second triad as a reward for this feat of valour.

in the harvest time The preposition does not mean in, and the reading of 1 Chronicles 11:15 to the rockis perhaps the true one.

the cave of Adullam David's old haunt in the valley of Elah. See note on 1 Samuel 22:1.

the valley of Rephaim See note on ch. 2 Samuel 5:18. The mention of the "hold" and this valley together in both narratives makes it not improbable that the exploit of the three heroes occurred in the invasion related in ch. 2 Samuel 5:17 ff.