Is this connected to the previous verse?
Radak: Yes. Via contemplating Your Edos, every moment secrets of them were revealed to me, so I realized that there is no end.
What is "l'Chol Tichleh"?
Rashi: Every matter has a limit, how much one can delve into it, except for Your Mitzvos.
Radak: For everything, I saw its end, except for Your Mitzvos.
Malbim: All worldly matters, to understand the purpose, it must have an end. The purpose is only if there is a final action, e.g. dwells in a house or sitting on a chair. However, there is no end to Mitzvos. Even so, there is a purpose. Every Mitzvah is an end unto itself. Also pursuing Mitzvos is an end unto itself. The primary purpose is to believe in Hashem and heed His commands, and the pleasing spirit in front of Him that He said, and His will was done.
Is there no limit to Mitzvos? They have a known number!
Radak #1: Their branches are without limit.
Radak #2: There is no limit to Mitzvos of the heart; Mitzvos of the body have a limit.
Ma'alos ha'Torah (DH v'Shamati me'Achi): Every word of Torah that left Hashem's mouth is a Mitzvah unto itself. There is no limit to Mitzvos! Anyone with an eye of intellect and an understanding heart can conduct all his matters, small or big, according to Torah and Mitzvos; he fulfills Mitzvos at every moment. We find many cases of this in the Gemara and Midrashim.
Why does it say "Mitzvascha" (singular)?
Radak: This refers to the Klal of Mitzvos, like "Ki ha'Mitzvah ha'Zos Asher Anochi Metzavecha ha'Yom" (Devarim 30:11).
