What is the meaning of "she'Sham Alu Shevatim"?
Rashi: Shevatim ascended to Shilo, when Yisrael ascended from Egypt and fixed the Mishkan in Shilo.
Radak: All 12 tribes ascended to Yerushalayim, and it contained all of them.
Malbim: The Shevatim ascended to there and were united via the city, since all gather there three times a year for one purpose, to thank Hashem. This is the inner force that ties the individual limbs. The city in which they gather is like the heart, in which is Ru'ach Chayim that keeps the body alive.
Why does it say "Shivtei Kah"?
Rashi: Refer to 122:4:2:1.
Radak: They guard His Mitzvos.
What is testimony for Yisrael?
Rashi (from Shir ha'Shirim Rabah 4:24): When Yisrael left Egypt, the nations said that they are Mamzerim. If the Egyptians ruled over Yisrael's bodies, all the more so over their wives! Hashem said, I will testify that they are the sons of their fathers 1 . Hashem put His name (Kah) on the Shevatim - ha'Reuveni, ha'Shimoni, a Yud at the end and a Hei at the beginning.
Radak: The miracles that Hashem showed for them in Yerushalayim testified that He chose them. One of them was that Yerushalayim could contain all the Shevatim - no one said, it is hard for me to find place to lodge in Yerushalayim (Avos 5:5). Another was that they all gathered in the Azarah; when they stood they were crowded, but when they bowed, they were not crowded.
Radak: This that the Shevatim ascended was testimony and a Mitzvah for Yisrael to go to there to thank Hashem.
I.e. their mother's husbands truly are their fathers. (PF)
