Why was Ruth in the Field?
(ט) וּֽבְקֻצְרְכֶם֙ אֶת־קְצִ֣יר אַרְצְכֶ֔ם לֹ֧א תְכַלֶּ֛ה פְּאַ֥ת שָׂדְךָ֖ לִקְצֹ֑ר וְלֶ֥קֶט קְצִֽירְךָ֖ לֹ֥א תְלַקֵּֽט׃ (י) וְכַרְמְךָ֙ לֹ֣א תְעוֹלֵ֔ל וּפֶ֥רֶט כַּרְמְךָ֖ לֹ֣א תְלַקֵּ֑ט לֶֽעָנִ֤י וְלַגֵּר֙ תַּעֲזֹ֣ב אֹתָ֔ם אֲנִ֖י יְהוָ֥ה אֱלֹהֵיכֶֽם׃
(9) When you reap the harvest of your land, you shall not reap all the way to the edges of your field, or gather the gleanings of your harvest. (10) You shall not pick your vineyard bare, or gather the fallen fruit of your vineyard; you shall leave them for the poor and the stranger: I the LORD am your God.
(כב) וּֽבְקֻצְרְכֶ֞ם אֶת־קְצִ֣יר אַרְצְכֶ֗ם לֹֽא־תְכַלֶּ֞ה פְּאַ֤ת שָֽׂדְךָ֙ בְּקֻצְרֶ֔ךָ וְלֶ֥קֶט קְצִירְךָ֖ לֹ֣א תְלַקֵּ֑ט לֶֽעָנִ֤י וְלַגֵּר֙ תַּעֲזֹ֣ב אֹתָ֔ם אֲנִ֖י יְהוָ֥ה אֱלֹהֵיכֶֽם׃ (ס)
(22) And when you reap the harvest of your land, you shall not reap all the way to the edges of your field, or gather the gleanings of your harvest; you shall leave them for the poor and the stranger: I the LORD am your God.

(ב) אין פוחתין לפאה מששים. ואף על פי שאמרו אין לפאה שיעור. הכל לפי גודל השדה ולפי רוב העניים ולפי רוב הענוה:

(2) One should not make the Peah less than one-sixtieth [of the entire crop]. And although they [the Sages] say that there is no definite amount given for Peah, it is all based upon the size of the field and upon the number of poor [who will be collecting it] and upon the abundance of the crop.