What is the significance of "Tachas ha'Shavet"?
Rashi: You will be submissive to Me and My Musar.
Radak: This is like "Kol Asher Ya'avor Tachas ha'Shavet" (Vayikra 27:32). I.e. like the flock, that one who counts them holds a staff and counts them one by one, and he takes out the 10th for Ma'aser 1 . So I will count you, and the sinner will perish. This counting is a Mashal. So Yirmeyah said (33:13) "Od Ta'avornah ha'Tzon Al Yedei Moneh." Yonason translates 'I will place on you the decree of My judgment, and raise you in Mesores of the Bris.
Malbim: The 10th is Kadosh, and the others remain in their Emunah.
What is "Mesores ha'Bris"?
Rashi: The Bris that I gave over to you.
Radak: The first letter of the root (Aleph) is omitted, It should say Me'useres, like "Machagores Sak" (Yeshayah 3:24). I will bind you in a Bris; you will never leave it.
Malbim: This is a new Bris mentioned above (Perek 16), which will be permanent. They will not return to sin, and He will not remove His Shechinah from them.
