Pirkei Avot §avot_02_16: He [Rabbi Tarfon] used to say: It is not your duty to finish the work, but ne...

He [Rabbi Tarfon] used to say: It is not your duty to finish the work, but neither are you at liberty to neglect it; If you have studied much Torah, you shall be given much reward. Faithful is your employer to pay you the reward of your labor; And know that the grant of reward unto the righteous is in the age to come.