Why does it say "Ra'u ba'Aron"?
Radak, from Bamidbar Rabah 8:9: They opened it to see what is inside.
Malbim: When Re'iyah is followed by the prefix Beis, it refers to insight in a matter and understanding it, e.g. "va'Yar b'Sivlosam" (Shemos 2:11). It usually refers to matters of intellect - "v'Al Er'eh b'Ra'asi" (Bamidbar 11:15), "u'Re'e b'Tuv Yerushalayim" (Tehilim 128:5). They looked at it more than is proper, amidst a lack of fear and honor.
It already said "va'Yach b'Anshei Beis Shemesh." Why does it say "va'Yach ba'Am"?
Malbim: "Ba'Am" refers to people who gathered from surrounding places.
Why does it say "Shiv'im Ish Chamishim Elef Ish"?
Rashi citing Targum Yonasan: [He killed] 70 elders and 50,000 in the congregation.
Rashi citing Sotah 35b: It was 70 men, each of whom was the equal of 50,000, or 50,000, each of whom was the equal of a Sanhedrin of 70.
Radak: It is 50,070 men. The Vov is omitted, like "Shemesh Yare'ach" (Chabakuk 3:11), "Reuven Shimon" (Shemos 1:2) and similar verses.
Malbim #1: It is 70 men who gathered from surrounding places (refer to 6:19:2:1), and 50,000 men of Beis Shemesh.
Malbim #2: It is 70 men among the 50,000 who gathered. It is as if it says me'Chamishim Elef. The prefix Mem is often omitted, e.g. "Elchanan Ben Dodo Beis Lechem" (Shmuel 2:23:24). Here it is omitted, for they were pained at the death of their brothers, and it seemed to them that they were all stricken.
