And Absalom and all the men of Israel said, The counsel of Hushai the Archite is better than the counsel of Ahithophel. For the LORD had purposed to defeat the good counsel of Ahithophel, to the intent that the LORD might bring evil upon Absalom.
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Augustine of Hippo
Accordingly, as the Scripture says, “And by the command of the Lord the good counsel of Ahithophel was defeated, that the Lord might bring evil upon Absalom.” The counsel of Ahithophel was called “good” because it served his purpose for the time, since it favored Absalom over his father whom he had risen up against in rebellion. And it might well have destroyed him if the Lord had not frustrated Ahithophel’s counsel by influencing the heart of Absalom to reject this counsel and to choose another which was not to his advantage. - "On Grace and Free Will 20.41"
Profitable, to the cause of Absalom, more than that of Chusai, which was also very plausible. (Haydock)
Lord. The Scripture always directs us to fix our thoughts on God, as the arbiter of all human affairs. (Calmet)
Hebrew, "for the Lord had ordained to dissipate the good counsel "(Haydock)
"Plerumque qui fortunam mutaturus est consilia corrumpit, efficitque, quod miserrimum est, ut quod accidit, etiam meritò accidisse videatur, et casus in culpam transeat "Peterc. ii.
For what shall we say about Hushai’s pious deception of Absalom for the sake of King David’s safety which, although formulated with good will by the deceiver and cheater and opposed to the well-being of the questioner, is approved by the text of divine Scripture that says, “By the will of the Lord the useful advice of Ahithophel was undone, so that the Lord might bring evil upon Absalom”? For what was accomplished with a right intention and pious judgment for a good purpose and conceived for the safety and religious victory of a man whose piety was pleasing to God, all by way of deception, could not be blamed. - "Conference 17.19.5"