What is "Yo'av's hand"?
Radak: It is his counsel and word.
Why did David suspect that Yo'av instructed her?
Malbim: The woman would not do so on her own. 1
Malbim did not explain how David knew that the one who counseled her was Yo'av. Perhaps he suspected that all her words were prepared; only Yo'av could do so (refer to 14:19:3:3). Alternatively, Yo'av was second to David in running the country; anyone else would fear to do so. Afterwards, when Avshalom asked Yo'av to ask about seeing David, and Yo'av did not go (verse 29), Avshalom did not ask anyone else! (PF)
What is the meaning of "Im Ish"?
Rashi, Targum Yonasan: It is like Im Yesh, and like ha'Yesh. Also "Od ha'Ish Beis Rasha" (Michah 6:10) is like ha'Yesh. Radak - our verse means, is there [reason] to veer right or left from everything that you said?! [No,] it is like you said; Yo'av told me.
Radak: "Ish" means 'man', just the Yud is omitted. Did someone else command me not to veer right or left from everything that I said?! No it is like you said - Yo'av told me. "Asher" is like Ka'asher. Also "Tochal Matzos Asher Tzivisicha" (Shemos 34:18) is like Ka'asher Tzivisicha. There is an omission amidst "mi'Kol Asher Diber"; it means mi'Kol Mah Asher Amarti 1 . Often words are omitted when the meaning is clear.
Malbim: He knew everything that you will say, and told me everything that I said. Only Yo'av, who is expert in royal etiquette, could command me about everything from the beginning to the end.
It seems that additionally, the word "Asher" is repeated and means Ka'asher, like Radak said. It is as if it says 'mi'Kol Asher Amarti Ka'asher Diber Adoni ha'Melech.' (PF)
