1)
What did Hashem mean when He instructed Moshe to see how He had begun to deliver Sichon ... ?
1.
Rashi #1: This teaches us that He bound the angel of the Emorim in Heaven and placed him under Moshe's feet, and Moshe placed his foot on his neck.
2.
Rashi #2: Refer to 3:24:3:2.
3.
Targum Yonasan: He was referring to the sun and moon standing still for the duration of the battle against Sichon. 1
2)
What is the translation of Hacheil Rash!"?
1.
Rashi, Targum Onkelos and nTargum Yonasan: 'Begin to drive them out!'