2 Samuel 3:11

And he could not answer Abner a word again
That is, he would not, he durst not; otherwise, if it was fact he charged him with, he could have insisted on the truth of it, and aggravated the crime and scandal of it; and observed it to him, that the kindness he had shown him was no excuse for it; but such things, though he would, he durst not say:

because he feared him;
he had the army at his command, and could dethrone him when he pleased; and it has been the fate of greater men than Ishbosheth to be awed by their generals, and even David himself; see ( 2 Samuel 3:39 ) .