Adam Clarke on 2 Samuel 4:11

How much more - Here are several things which aggravated the guilt of those wicked men.

1. Ish-bosheth was an innocent man, and therefore none could have any ground of quarrel against him.

2. He was in his own house, which was his sanctuary, and none but the worst of men would disturb him there.

3. He was upon his bed, resting in the heat of the day, and so free from suspicion that he was not even attended by his guards, nor had he his doors secured. To take away the life of such a man, in such circumstances, whom also they professed to hold as their sovereign, was the most abandoned treachery.