First Hadith
From ʿĀʾishah (may Allah be pleased with her): The Messenger of Allah (blessings and peace be upon him) purchased some food from a Jew and left his iron coat of mail with him as collateral.

Overall meaning
The Prophet’s detachment from this worldly life, his sparse use of it, and his matchless generosity had left him with nothing stored away—even for a few days’ provisions for himself and his family. Consequently, he came to the point where he bought barley from a Jew and pawned the very item he needed for striving in Allah’s cause and exalting His word—his coat of mail, which he wore in battle as protection, after Allah, against the enemy’s weapons and schemes.

Lessons derived from the ḥadith
1- The permissibility of taking a pledge (rahn); the Qur’an also affirms it.
2- Legitimate commercial dealings with non-Muslims are allowed and are not the prohibited form of reliance upon them. Al-Sanʿānī said: This is incontrovertible in the religion, for the Prophet and his Companions lived in Mecca for thirteen years dealing with the polytheists, and he lived in Medina for ten years dealing—together with his Companions—with the People of the Book and frequenting their markets.
3- It is permissible to transact with someone whose wealth is largely unlawful, provided one does not know that the very item being exchanged is itself unlawful. Al-Sanʿānī remarks that we are not required to investigate how they conduct their own dealings; it is well known that they sell wine and consume illicit earnings, yet we are not charged with scrutinising their transactions or how money reaches their hands. Rather, we treat what is in their possession as lawful property until the contrary becomes evident. The same ruling applies to oppressive rulers.
4- The narration does not permit selling weapons to non-Muslims. A coat of mail is not itself a weapon, and a pledge is not a sale. Moreover, the Jew who held the Prophet’s coat was a mustaʾmin—under Muslim protection and supervision—so no aggression or treachery was feared. Assisting disbelievers or enemies with weaponry is forbidden and a grave betrayal.
5- The report showcases the Prophet’s austerity and renunciation, seeking what is with Allah and displaying such generosity that no wealth was allowed to remain idle in his possession.