"And Isaac sowed [in that land and found in that year a hundredfold]" (Genesis 26:12). He took all the tithe from his wealth and sowed [it as] charity for the poor, just as you say, "sow for yourselves according to charity" (Hosea 10:13). And for each and every thing that he tithed, the Holy One, blessed be He, gave him a hundred gates of blessings. "And Abimelech charged all the people, saying: he that touches [this man or his wife shall surely be put to death]" (Genesis 26:11). Rabbi Aibo said: [it was forbidden] that a man should not even throw a pebble at him.
Isaac Sowed Charity and Reaped a Hundredfold Blessing
Yalkut Shimoni on Torah 111:11
וַיִּזְרַע לָקַח כָּל הַמַּעֲשֵׂר מִמָּמוֹנוֹ וְזָרַע צְדָקָה לַעֲנִיִּים, כְּשֵׁם שֶׁאַתָּה אוֹמֵר, (הושע י, יג) "זִרְעוּ לָכֶם לִצְדָקָה", וְכָל דָּבָר וְדָבָר שֶׁעִשֵּׂר נָתַן לוֹ הַקָּדוֹשׁ בָּרוּךְ הוּא מֵאָה שְׁעָרִים שֶׁל בְּרָכוֹת. וַיְצַו אֲבִימֶלֶךְ אֶת כָּל הָעָם לֵאמֹר הַנֹּגֵעַ, אָמַר רַבִּי אֵיבוֹ אֲפִילוּ צְרוֹר לֹא יִזְרֹק בּוֹ אָדָם.