Abu Ishaq narrates from al-Aliyah that she said: I was sitting with Sayyidah Aishah (may Allah be pleased with her) when Umm Muhabbah came and said: O Mother of the Believers! Do you know Sayyiduna Zayd bin Arqam (may Allah be pleased with him)? Sayyidah Aishah (may Allah be pleased with her) said: Yes. (She said:) I sold him my slave-girl for 800 dirhams on credit, until his stipend comes, and he wanted to sell her, so I bought her from him for 600 dirhams in cash. Sayyidah Aishah (may Allah be pleased with her) said to Umm Muhabbah: Evil is what you bought and evil is what he bought. Convey my word to Zayd: if he does not repent, he has nullified even his jihad done with the Prophet (peace and blessings be upon him).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10799