Moses appeals to the good sense of the people themselves: How can I myself alone bear your cumbrance, and your burden, and your strife? Cumbrance: this is a just rendering of the Hebrew word מֹרֲח, from טָרַח, which, though it occurs only in the Hiphil in Hebrew, in the sense of to cast down (Job 17:11), probably was in use also in the Kal, in the sense of to lay upon, to encumber, which is the meaning of the cognate Arabic, see Arabic word, followed by, see Arabic word.
Burden ( שָּׁא, from נָשָׂא, to lift up, to carry, to bear), something lifted up and carried, a load or burden. Strife: ( רִיב) here, not mere contention, but litigation, suit-at-law. Some understand all these three, of troubles and burdens laid upon Moses, by his being called upon to compose differences, and adjust competing claims among the people.
But other burdens besides these came upon him as the leader of the nation; and it seems best, therefore, to understand the first two of troubles and burdens generally.