Charles Ellicott Commentary 2 Samuel 17

Pursue after David this night. — Ahithophel saw clearly that Absalom’s success depended on striking an immediate blow. He felt confident, and perhaps with reason, that David in his distress and weariness was in no condition to resist a sudden onset. That his counsel was wise is made evident by the opposition of Hushai and the anxiety to send word to David with all haste. “This night” is generally understood to mean the night of the day on which David left Jerusalem; but from 2 Samuel 17:16 and 2 Samuel 15:28, it appears that he was already encamped by the fords of the Jordan, a greater distance than he could have accomplished in one day’s march.

Will make him afraid. —This translation is hardly strong enough. The thought is that Ahithophel will throw his band into a panic by a sudden night attack, and in the confusion will easily secure the person of the king.

Bring back all the people. —This evil counsellor, with artful flattery, assumes that Absalom is the rightful king, and that the people who have gone off after David only need to be brought back to their allegiance.

Call now Hushai. —The good sense of Absalom and all the people immediately approved the counsel of Ahithophel; but, at such an important crisis, Absalom also sought the advice of his father's other famous counselor.

Not good at this time. —The words, at this time, should be transposed. What Hushai says is This time the counsel of Ahithophel is not good, implying that his previous advice (2 Samuel 16:21) had been wise, thus assuming an appearance of candor.