Rashi: To teach us that, even if, in spite of the potential punishment for judging alone, ¹ he would be willing to do so, he would not be able to since, as he already informed them, ² the decision was not his, but Hashem's.

Seforno: The gist of the Pasuk is to rebuke the people on the fact that, even after he informed them of their imminent entry into Eretz Cana'an, ³ they continued to squabble over monetary issues, until it reached a point that he had to organize judges and even to go so far as to appoint one judge for every ten people. ⁴

Rashi: "Torchachem" is where, for example, one of the litigants would see that the other side was winning the case, he would claim that he had more witnesses, more proofs or that that he wanted to add more judges; ¹ "Masa'achem" is where, when Moshe left the Beis-Din early, they would accuse him of having trouble with Shalom Bayis, whereas "Rivchem" simply means their quarrelsomeness.

Ramban #1: They refer to the three things that Moshe told Yisro ² with reference to his status as the sole judge ³ : 1. To teach them Torah ("Torchachem"); ⁴ 2. To Daven on their behalf ("Masa'achem"), ⁵ and 3. To litigate between the quarreling parties ("Rivchem").

Seforno: "Torchachem" refers to their quarrels over general issues, "Mas'a'achem", to communal issues and "Rivchem", to quarrels over money-matters.

Targum Yonasan: "Torchachem" refers to heretical issues, ⁶ "Mas'a'achem", to their wicked thoughts concerning himself, ⁷ and "Rivchem", to their devious behavior in court, where they would give a Sela in order to extract two, ⁸ or two, to extract three.