1)
What is the meaning of "Heref"?
1.
Rashi citing Targum Yonasan: Wait.
2.
Malbim: Denying your sin is a great Aveirah - "Hineni Nishpat Osach Al Amrech Lo Chatasi" (Yirmeyah 2:35). Cease talking, and I will tell you what Hashem said!
2)
Why is it written va'Yomeru, and we pronounce it va'Yomer?