In the previous verse Joab had told Benaiah to go ahead and kill him where he was standing (holding on to the corners of the altar) and this had been reported to Solomon. This is why Solomon now says Do as he has said ….

Strike him down: See the comments on this expression in verse 25.

Thus: This Revised Standard Version rendering reflects nothing more than the common Hebrew conjunction. But it is clear that Solomon sees a logical relationship between the killing of Joab and the removal of guilt from himself and from the other descendants of David. Joab’s death would compensate for the crimes he had committed and in this way the family of David would no longer be considered guilty.

After the verb take away, the Septuagint adds the word “today.” This addition is found in New Jerusalem Bible, but Critique Textuelle de l’Ancien Testament gives an {A} rating to the Masoretic Text, which should be followed.

From me and from my father’s house means from Solomon and from all of David’s other descendants.

The guilt for the blood which Joab shed without cause: Joab had killed Abner and Amasa, who were both innocent (verse 32). The Hebrew expresses this as “the guiltless blood that Joab shed” (see also 1 Sam 25.31). But in many languages a more natural model will be “the guilt of Joab, who executed people who had done no wrong” or “… who has killed innocent people” (New Century Version).

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on 1-2 Kings, Volume 1. (UBS Helps for Translators). New York: UBS, 2008. For this and other handbooks for translators see here .