(Genesis 14:24) Rava said: stolen property that has been eaten is hard [to remedy], for even wholly righteous men cannot restore it, as it is said, "except only what the young men have eaten" (Genesis 14:24) (Chullin 89a). This is what is written: "and every wicked and worthless man among the men who had gone with David answered... and David said, You shall not do so, my brothers, with what the LORD has given us, He who has protected us... and who will listen to you in this matter?... And it was from that day and onward [vama'alah] that he made it a statute" (1 Samuel 30:22-25). It does not say "and onward [vahal'ah]" here, but rather "and upward [vama'alah]" — from whom did he learn it? From Abraham his ancestor, who said, "except only what the young men have eaten" (Genesis 14:24).
Rava on Consumed Stolen Goods and How David Learned From Abraham
Yalkut Shimoni on Torah 76:5
(בראשית יד כד) אָמַר רָבָא, קָשֶׁה גֶּזֶל הַנֶּאֱכָל שֶׁאֲפִלּוּ צַדִּיקִים גְּמוּרִים אֵינָן יְכוֹלִין לְהַחֲזִירוֹ, שֶׁנֶּאֱמַר, בִּלְעָדַי רַק אֲשֶׁר אָכְלוּ הַנְּעָרִים וְגוֹ' (חולין פט.). הֲדָא הוּא דִּכְתִיב, (שמואל א ל, כב כה) "וַיַּעַן כָּל אִישׁ רָע וּבְלִיַעַל מֵהָאֲנָשִׁים אֲשֶׁר הָלְכוּ עִם דָּוִד וְגוֹ' וַיֹּאמֶר דָּוִד לֹא תַּעֲשׂוּ כֵן אֶחָי אֵת אֲשֶׁר נָתַן ה' לָנוּ וַיִּשְׁמוֹר אוֹתָנוּ וְגוֹ' וּמִי יִשְׁמַע לָכֶם לַדָּבָר הַזֶּה וְגוֹ' וַיְּהִי מֵהַיּוֹם הַהוּא וָמָעְלָה וַיְּשִׂימֶהָ לְחֹק" וְגוֹ'. וְהָלְאָה אֵין כְּתִיב כָאן, אֶלָּא "וָמָעְלָה" מִמִּי לָמַד, מֵאַבְרָהָם זְקֵנוֹ, שֶׁאָמַר בִּלְעָדַי רַק אֲשֶׁר אָכְלוּ הַנְּעָרִים.