וַיִּשָּׂ֨א מַשְׂאֹ֜ת מֵאֵ֣ת פָּנָיו֮ אֲלֵהֶם֒ וַתֵּ֜רֶב מַשְׂאַ֧ת בִּנְיָמִ֛ן מִמַּשְׂאֹ֥ת כֻּלָּ֖ם חָמֵ֣שׁ יָד֑וֹת וַיִּשְׁתּ֥וּ וַֽיִּשְׁכְּר֖וּ עִמּֽוֹ׃
And portions were taken unto them from before him; but Benjamin’s portion was five times so much as any of theirs. And they drank, and were merry with him.
Rashbam on Genesis
ותרב, as if the Torah had written ותרבה. The meaning is that Binyamin’s gift from Joseph was far greater than the gift received by his brothers. A parallel construction to the word vaterev appears in connection with the construction of the Tabernacle ותכל, vatechel, where it means that the construction had been completed (Exodus 39,32).
Sforno on Genesis
ותרב משאת בנימין, to see if the brothers would display signs of jealousy.