Why does the Torah insert the words "be'Chol Moshvoseichem"?
Ramban: Beis-Din are obligated to convene at all times, even after the Churban and even in Galus, to judge fines, thefts, wounding and other monetary issues, and laws that concern lashes. 3
See Sifsei Chachamim.
See Ramban's objection to this explanation.
Ramban (citing Sanhedrin, 52b and Mechilta): Based on the Pasuk in Devarim 17:9, they may only adjudicate with regard to the laws that involve Misas Beis-Din as long as the Kohanim are serving in the Beis-Hamikdash, but not after the Churban. This is because we expound "Chukas Mishpat" in this Pasuk only in connection with the laws of Misah - mentioned earlier in Pasuk 12, 24 - See Ramban.