Albert Barnes Commentary 2 Samuel 17:7

"And Hushai said unto Absalom, The counsel that Ahithophel hath given this time is not good." — 2 Samuel 17:7 (ASV)

At this time - Rather, “The counsel that Ahithophel has given this time is not good.” He contrasts it with the counsel given before (2 Samuel 16:21), which was good. This gave his conduct an appearance of candor, and thus added weight to his dissent. Observe the effect of David’s prayer in 2 Samuel 15:31.