What is the meaning of "me'Heichalecha Al Yerushalayim"?
Rashi: From what the kings saw the honor of Your Heichal, which is on Yerushalayim, they will bring to You gifts.
Radak #1: Some say that the prefix Mem in me'Heichalecha is like a Beis 1 . Also "Hashem mi'Sinai Ba" (Devarim 33:2) is like b'Sinai.
Radak #2: This is like "Nora Elokim mi'Mikdashecha" (verse 36). From Your Heichal, where Your honor dwells, went out on Yerushalayim the strength that saved us from the enemy.
Malbim: You [Hashem's strength] did so from your Heichal (Yerushalayim), where Hashem's strength dwells.
What is the significance of the gifts that kings will bring to Hashem?
Radak: Since Yerushalayim was saved, but not other Arei Yehudah, the kings will recognize that the strength comes to Yisrael from Your honor that dwells among them.
Malbim: The gifts that they will bring belong to You. This hints that To'i, Melech Chamas, sent to David Kelim of gold and silver for striking Hadad'ezer, and David was Makdish them to Hashem.
