Numbers 35:29

In all your dwelling places. This teaches that the lower Sanhedrin court functions outside the land so long as it functions in Eretz Yisroel.

And these indications shall be to you a decree of judgment for your generations in all your dwellings:

IN ALL YOUR HABITATIONS. “This teaches us that a Sanhedrin may function outside the Land [of Israel] as long as one functions in the Land of Israel itself.” This is Rashi’s language. This is indeed correct, because after the destruction [of the Temple] the Sanhedrin cannot function in the Land of Israel nor outside it, just as our Rabbis have said in the Chapter Arba Mithoth Beth Din: “And thou shalt come unto the priests the Levites, and unto the judge that shall be in those days — when there is a priest [performing the Divine Service in the Sanctuary] there is [execution of] judgment; when there is no priest [at the Sanctuary] there is no judgment.” And we have been taught in the Mechilta: “Whence do we know that judicial execution can take place only during the existence of the Sanctuary? Because it says, From Mine altar, thou shalt take him, that he may die. If you have an altar, you may render capital punishment, and if not, you may not do so.”
But I have nowhere found in connection with a commandment which is limited to the [duration of the] existence of the Sanctuary that Scripture should say about it, throughout your generations in all your habitations [as it does here], because this [expression] indicates [the contrary, namely that it is binding] even during the exile, outside the Land. Thus [it uses this expression] in connection with [the obligation of] abstaining from work on the Festival of Shavuoth,. and in connection with the prohibition of [eating from] the new crop [before bringing the omer on the sixteenth day of Nisan],, Verse 14. For the explanation of the word omer, see Vol. III, p. 368, Note 243. in order to make [these laws] obligatory even outside the Land [of Israel] and even nowadays [when the Temple is destroyed], so that we should not [think that the prohibition against eating of the new crop is] dependent upon [the actual offering of] the omer, and [so that we should not make the commandment to abstain from work on Shavuoth dependent] upon the offering of the new meal-offering, Verse 16. [on that day]. Likewise [the expression throughout your generations in all your habitations is used] in connection with [the prohibition against eating certain] fats, 3:17. so that we should not think that it is dependent upon the offerings. [And so here too the expression throughout your generations in all your dwellings would indicate that the execution of judgment including the death-penalty, applies at all times, and is not dependent upon the existence of the Sanctuary!] Perhaps the Rabbis interpreted the words [in our verse here]: And these things shall be for a statute of judgment [as referring not to the criminal cases mentioned in this section, but] to [the general law of] the Sanhedrin mentioned continually in this section, as it is said, [until he stand] before ‘the congregation’ for judgment; then ‘the congregation’ shall judge,, Verse 24. and Scripture is thus saying that we should always have, throughout all generations, and even after the destruction [of the Sanctuary], “a congregation that judges” [i.e., a Sanhedrin, or court] in order to adjudicate upon the laws of fines, robberies, personal injury, and all monetary matters, and to deal with the law of forty stripes.