How long will ye imagine mischief - The original word, תהותתו tehothethu, has been translated variously; rush upon, rage against, stir yourselves up, thrust against: the root is התת hathath or התה hathah, to rush violently upon, to assault. It points out the disorderly riotous manner in which this rebellion was conducted.
As a bowing wall - a tottering fence - Ye are just ready to fall upon others, and destroy them; and in that fall yourselves shall be destroyed: "Ye shall be slain the whole of you."
How long will ye imagine mischief against a man? - The original word here rendered “imagine mischief,” from התת hâthath occurs only in this place. It means, according to Gesenius (Lexicon), to break in upon; to set upon; to assail: “How long will ye break in upon a man?” that is, set upon him. So the Septuagint, and the Latin Vulgate. It does not refer to their merely forming purposes of mischief against a man, but to their making assaults upon him; to their endeavoring to take his life or to destroy him. The address here is to the enemies of David, and the language would apply well to the attempts made upon his life by Absalom and his followers. The question here is, “how long” they would continue to do this; how long they would show this determined purpose to take his life; whether they would never cease thus to persecute him. They had already done it long; they had showed great perseverance in this course of wickedness; and he asks whether it would never come to an end? Who these persons were he does not intimate; but there can be no great danger of mistake in referring the description to Absalom and his adherents.
Ye shall be slain all of you - Prof. Alexander renders this entire passage,” Will ye murder (that is, seek to murder him) all of you (combined against a single person, who is consequently) like wall inclined (or bent by violence), fence (or hedge) crushed (broken down).” So, substantially, DeWette renders it. Those who thus interpret the passage give it an active signification, meaning that his enemies pressed upon him, like a wall that was bent by violence, or a fence that was likely to fall on one. The original word rendered “ye shall be slain,”
d tªraatsªchuw - תרצחוּ terâtsechû is in the active form (Piel), and cannot without violence be rendered in the passive, as it is in our translation. But the active form may still be retained, and a consistent meaning be given to the whole passage without the forced meaning put on it in the rendering by Prof. Alexander. It is not natural to speak of enemies as so coming on a man as to make him like a falling wall, or a tottering fence. The evident idea is, that they themselves would be as a falling wall; that is, that they would be defeated or disappointed in their purpose, as a wall that has no solid foundation tumbles to the ground. The meaning of the original may be thus expressed: “How long will ye assail a man, that ye may put him to death? All of you shall be as a bowing wall,” etc. That is, You will not accomplish your design; you will fail in your enterprise, as a wall without strength falls to the ground.
As a bowing wall - A wall that bows out, or swells out; a wall that may fall at any moment. See the notes at Isaiah 30:13.
And as a tottering fence - A fence that is ready to fall; that has no firmness. So it would be with them. Their purposes would suddenly give way, as a fence does when the posts are rotted off, and when there is nothing to support it.