וַיַּקְרֵ֥ב מֹשֶׁ֛ה אֶת־מִשְׁפָּטָ֖ן לִפְנֵ֥י יְהוָֽה׃ (ס)
האָט משה געבראַכט זײער משפּט פֿאַר גאָט.
Rashi
ויקרב משה את משפטן AND MOSES BROUGHT THEIR CAUSE [BEFORE THE LORD] — The law on this subject escaped him (Sanhedrin 8a). Here he received punishment because he had assumed a “crown” (he had set himself up as the supreme judge) by saying, (Deuteronomy 1:17) “And the cause that is too hard for you ye shall bring to me”. Another explanation: This chapter ought to have been written by Moses (i.e., like most laws in the Torah it should have been spoken to the people by Moses without his having waited until some incident made its promulgation necessary), but for the fact that the daughters of Zelophehad had so much merit, it was therefore written through them (it was their complaint which gave occasion for stating it) (Bava Batra 119a; Sanhedrin 8a).
Or HaChaim
ויקרב משה את משפטן לפני השם, "Moses submitted their claim for G'd to adjudge." It is possible, that Moses used the last mentioned arguments of these daughters and wanted to know from G'd if to treat these girls as the missing sons or if to treat their mother as a potential candidate for some kind of levirate marriage in order to preserve the name of their father. Moses hoped that in the event G'd would deny them an inheritance, He would at the same time give him a reason why the principle underlying the levirate marriage legislation did not apply to them, i.e. why their mother could not marry a brother-in-law and the son born from such a marriage would inherit Tzelofchod's or Chefer's inheritance.
Rabbeinu Bahya
ויקרב משה את משפטן לפני ה', “Moses presented their judicial claim to the Lord.” Some commentators feel that the reason that Moses disqualified himself from presiding over the court dealing with the claim of the daughters of Tzelofchod was precisely because they had made a point of stating that their father had not been someone who had personally hated, i.e. opposed Moses. If he were to judge their case he might be accused of being prejudiced in their favour as a result of their having made such a statement. I do not believe that this is plausible at all. If this evaluation were correct Moses did not have to turn to G’d but could have let this case be decided by a tribunal from which he personally had excused himself.