וַיֹּאמְרוּ֮ לֹ֣א נוּכַל֒ עַ֣ד אֲשֶׁ֤ר יֵאָֽסְפוּ֙ כָּל־הָ֣עֲדָרִ֔ים וְגָֽלֲלוּ֙ אֶת־הָאֶ֔בֶן מֵעַ֖ל פִּ֣י הַבְּאֵ֑ר וְהִשְׁקִ֖ינוּ הַצֹּֽאן׃
Y ellos respondieron: No podemos, hasta que se junten todos los ganados, y remuevan la piedra de sobre la boca del pozo, para que abrevemos las ovejas.
Rashi on Genesis
לא נוכל WE CANNOT — give them water because the stone is a heavy one.
Siftei Chakhamim
To give them drink because the stone is large. Rashi is explaining that they cannot roll it due to its weight, as Rashi said on v. 3, and not because they had so agreed among themselves.
Rashi on Genesis
וגללו AND THEY ROLL AWAY — This word is rendered in the Targum by ויגנדרון “and they will roll away” (whilst in Genesis 5:3 it is rendered by an Aramaic participle) because the verb has here a future meaning.