It is clear from verse 8 that Ish Boshes said this. Why does our verse not say who said this?
Radak: The previous verse mentioned Beis Sha'ul, which refers to Ish Boshes.
Kli Yakar #1: Perhaps it is because he said so via a Shali'ach. He was ashamed to say so himself to Avner.
Kli Yakar #2: Now, Ish Boshes did not conduct like his name, to be ashamed to say such a thing, therefore his name is not mentioned.
Why did he censure Avner for this?
Radak: If it was true, (a) He censured him due to his father's honor. (b) She was forbidden to him, for only a king may marry a king's widow. Even though she was only a concubine, since she was designated for Sha'ul, she was considered a king's widow. One may not use even a king's scepter!
Malbim: Since only a king may marry her, Ish Boshes considered this Mored b'Malchus.
Was the accusation true?
Mahari Kara (8): No.
Radak: He suspected him of this.
Malbim: Yes. Since he was the kingship's support, he thought that matters of kingship apply to him. 1
