1)
Why does it say "v'Im Amdu b'Sodi"?
1.
Rashi: Had they heard My words, they should have informed My nation of My words and Torah, and to make them err and stray from me. Malbim - this shows that they did not hear My words! Hashem would not send a Navi to say that they will have Shalom, and need not repent!
2)
Why does it say "va'Yishme'u" with the prefix Vov?
1.
Radak: This shows a stipulation - if this will be (they heard me), this will be (they would have made the nation repent). This is like "v'Tam'ah Shevu'ayim k'Nidasah", "v'Nasati Gishmeichem" (Vayikra 12:5, 26:4) and similar verses.
