A man from Hamdan came to Ibn Mas'ud (may Allah be pleased with him) on a piebald horse and said: A man has made me the executor of his will and has left an orphan; may I buy this horse, or another horse, from his wealth? Abdullah (may Allah be pleased with him) said: Do not buy anything from his wealth. And in the written record it reads: Do not buy anything from his wealth, and do not borrow anything from his wealth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12678