Reference for Keritot 37:35

לא נחלקו על העושה מלאכה בין השמשות שהוא פטור שאני אומר

SAID R'JUDAH: EVEN IF HE INTENDED TO PICK FIGS AND HE PICKED GRAPES, OR GRAPES AND HE PICKED FIGS, WHITE [GRAPES] AND HE PICKED BLACK ONES, OR BLACK AND HE PICKED WHITE ONES, R'ELIEZER DECLARES HIM LIABLE AND R'JOSHUA DECLARES HIM EXEMPT.

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