טוֹחֵן הַרְבֵּה וּמוֹצִיא קִמְעָא

ביטוי (אנגלית)

Grinds much and produces little/ to toil much and produce little

הגדרה (אנגלית)

Figuratively: someone who studies or works a great deal but retains or gains very little; much effort, little result.

("Issi ben Yehudah used to enumerate the praises of the sages: Rabbi Meir—wise and a scribe... Rabbi Shimon—grinds much and produces little" - Gittin 67a)