Responsa for Peah 1:1
אֵלּוּ דְבָרִים שֶׁאֵין לָהֶם שִׁעוּר. הַפֵּאָה, וְהַבִּכּוּרִים, וְהָרֵאָיוֹן, וּגְמִילוּת חֲסָדִים, וְתַלְמוּד תּוֹרָה. אֵלּוּ דְבָרִים שֶׁאָדָם אוֹכֵל פֵּרוֹתֵיהֶן בָּעוֹלָם הַזֶּה וְהַקֶּרֶן קַיֶּמֶת לוֹ לָעוֹלָם הַבָּא. כִּבּוּד אָב וָאֵם, וּגְמִילוּת חֲסָדִים, וַהֲבָאַת שָׁלוֹם בֵּין אָדָם לַחֲבֵרוֹ, וְתַלְמוּד תּוֹרָה כְּנֶגֶד כֻּלָּם:
These are the things that have no measure: <i>Peah</i> [corner of the field which, while harvesting, must be left for the poor], <i>Bikurim</i> [First-fruits that must be brought to the Temple and given to the priest], the appearance-sacrifice [brought to the Temple on Pilgrimage Festivals], acts of kindness, and the study of the <i>Torah</i>. These are things the fruits of which a man enjoys in this world, while the principal remains for him in the World to Come: Honoring one's father and mother, acts of kindness, and bringing peace between a man and his fellow. But the study of <i>Torah</i> is equal to them all.