Bava Metzia 42A

מתני׳ המפקיד מעות אצל חברו, צררן והפשילן לאחוריו, או שמסרם לבנו ולבתו הקטנים, ונעל בפניהם שלא כראוי ⁠– חייב, שלא שימר כדרך השומרים. ואם שימר כדרך השומרים ⁠– פטור.

Mishnah: In the case of one who deposited coins with another, and that bailee bound it in a cloth and slung it behind him, or conveyed them to his minor son or daughter for safeguarding, or locked the door before them in an inappropriate, i.e., insufficient, manner to secure them, the bailee is liable to pay for the coins, as he did not safeguard the coins in the manner typical of bailees. But if he safeguarded the money in the manner that bailees safeguard items and it was nevertheless stolen, he is exempt.

גמ׳ בשלמא כולהו שלא שימר כדרך השומרים. אלא צררן והפשילן לאחוריו, מאי הוה ליה למיעבד? אמר רבא אמר רבי יצחק אמר קרא: ״וצרת הכסף בידך״, אף על פי שצרורין ⁠– יהיו בידך.

Talmud: Granted, for all the other cases, the bailee is liable to pay, as he did not safeguard the money in the manner that bailees safeguard items. But if the bailee bound it in a cloth and slung it behind him, what more was he to do? Rava says that R' Yitzḥak said: The verse states: “And you should bind up the money in your hand” (Deuteronomy 14:25), from which it is derived: Although it is bound, in order to safeguard the money, it must be in your hand.

ואמר רבי יצחק: לעולם יהא כספו של אדם מצוי בידו, שנאמר: ״וצרת הכסף בידך״. ואמר רבי יצחק: לעולם ישליש אדם את מעותיו, שליש בקרקע, ושליש בפרקמטיא, ושליש תחת ידו.

And apropos that verse, R' Yitzḥak says: A person’s money should always be found in his possession. He should not invest all of his money, leaving him with no money available for expenditures, as it is stated: “And you should bind up the money in your hand.” And R' Yitzḥak says: A person should always divide his money into 3; he should bury 1/3rd in the ground, and invest 1/3rd in business [bifrakmatya], and keep 1/3rd in his possession.