1)
What did Hashem mean when He said "Hachilosi Teis Lefanecha"?
1.
Rashi #1: He meant that He had 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 meant that the miracle of the sun and moon standing still in the sky was a sign that they would defeat Sichon.
2)
What is the meaning of "Hacheil Rash"?
1.
Targum Onkelos and Targum Yonasan: With reference to Sichon, it means 'Begin to drive Sichon out!'
2.
Yerushalmi Shevi'is, 6a: The insertion of the word "Hachel" implies that Hashem has rendered Sichon's land Chulin 1 - for Yisrael to conquer.