(1) You shall not watch your bother's ox or sheep run away, and ignore it. You must return it to your brother (2) And if your brother is not close to you, and you don't know him, then you shall bring it home to your house, and it shall be with you until your brother claims it, and you shall give it back to him. (3) And so shall you do with his donkey; and so shalt you do with his garment; and so shalt thou do with every lost thing that belongs to your brother, which he has lost, and you have found.
הפקר
Hefker = property that is declared ownerless and is available for anyone to take. Property becomes hefker by the owner declaring it so, or if it is a found object that can not be identified by its markings. Some examples include commonly scattered objects like coins and items that many people have the exact same version of like a simple #2 pencil.
Talmud, Bava Metzia 27a
Raba said: Why did the Torah enumerate ox, ass, sheep and garment?
They are all necessary: For had the Divine Law mentioned 'garment' alone, I would have thought: That is only if the object itself can be identified by witnesses,
or the object itself bears marks of identification. But in the case of a donkey, if only its saddle is attested or its saddle bears marks of identification, I might think that it
is not returned to him. Therefore the Torah wrote ‘donkey,' to show that even the donkey [is returned] in virtue of the identification of its saddle.
For what purpose did the Divine Law mention 'ox' and 'sheep'?' — 'Ox', that even the hair of its tail, and 'sheep', that even its shearings [must be returned].
If so, let the Torah mention 'ox', showing that even the the hair of its tail [must be returned], and the shearings of a sheep [which are more substantial] would be obvious?
Rather, said Raba… 'sheep' in connection with a lost article, is incomprehensible [i.e. superfluous] according to all opinions.
השבת אבידה מאיזה מקום חייב להשיבה. ובו ט"ס:
הרואה אבידת ישראל חייב לטפל בה להשיבה לבעליה שנאמר השב תשיבם ואם נטלה ע"מ לגזלה ועדיין לא נתייאשו הבעלים ממנה עובר משום השב תשיבם לאחיך ומשום לא תגזול ומשום לא תוכל להתעלם ואפי' אם יחזירנה אח"כ כבר עבר על לא תוכל להתעלם נטלה לפני יאוש על דעת להחזירה ולאחר ייאוש נתכוון לגזלה אינו עובר אלא משום השב תשיבם המתין עד אחר יאוש ונטלה אינו עובר אלא משום לא תוכל להתעלם:
דין אבידת עוברי עבירה. ובו ה סעיפים:
אבידת העכו"ם מותרת שנא' אבידת אחיך והמחזירה ה"ז עובר עבירה מפני שהוא מחזיק ידי עוברי עבירה ואם החזירה לקדש את השם כדי שיפארו את ישראל וידעו שהם בעלי אמונה ה"ז משובח ובמקום שיש חילול השם אבידתו אסורה וחייב להחזירה ובכל מקום מכניסים כליהם ככלי ישראל מפני דרכי שלום:
אֲבֵדַת עוֹבֵד עַכּוּ''ם מֻתֶּרֶת שֶׁנֶּאֱמַר (דברים כב ג) "אֲבֵדַת אָחִיךָ". וְהַמַּחֲזִירָהּ הֲרֵי זֶה עוֹבֵר עֲבֵרָה מִפְּנֵי שֶׁהוּא מַחֲזִיק יַד רִשְׁעֵי עוֹלָם. וְאִם הֶחֱזִירָהּ לְקַדֵּשׁ אֶת הַשֵּׁם כְּדֵי שֶׁיְּפָאֲרוּ אֶת יִשְׂרָאֵל וְיֵדְעוּ שֶׁהֵם בַּעֲלֵי אֱמוּנָה הֲרֵי זֶה מְשֻׁבָּח. וּבְמָקוֹם שֶׁיֵּשׁ חִלּוּל הַשֵּׁם אֲבֵדָתוֹ אֲסוּרָה וְחַיָּב לְהַחְזִירָהּ. וּבְכָל מָקוֹם מַכְנִיסִין כְּלֵיהֶם מִפְּנֵי הַגַּנָּבִים כִּכְלֵי יִשְׂרָאֵל מִפְּנֵי דַּרְכֵי שָׁלוֹם:
Ramb"m laws of Malveh veLoveh chapter 5
1. One may lend money to and borrow money from a gentile and a resident alien at interest, as implied by Deuteronomy 23:20: "Do not offer interest to your brother." We may infer: Offering - and taking - interest from "your brother" is prohibited; from people at large, by contrast, it is permitted.
It is a positive mitzvah to lend money to a gentile at interest, as Ibid:21 states: "You may offer interest to a gentile." The Oral Tradition teaches that this is a positive commandment. This is the Scriptural Law.
2. Our Sages, however, forbade a Jew from lending money to a gentile at a fixed rate of interest beyond what is necessary for him to earn his livelihood. They enacted this decree lest, the lender learn from the gentile's deeds as a result of the large extent of his contact with him. Therefore even according to the Sages, it is permitted to borrow money from a gentile at interest, for the Jew will flee from him, and will not frequent his company.
Torah scholars will not learn from a gentile's conduct. . Hence, it is permitted for them to lend money to a gentile at interest, even to make a profit. Any transactions in the category of "the shade of interest" that involve gentiles are permitted for everyone.