It is narrated from Sayyidah Aishah (may Allah be pleased with her) that Sayyiduna Abu Bakr (may Allah be pleased with him) had a slave who used to bring him (his earnings), and Sayyiduna Abu Bakr (may Allah be pleased with him) used to eat from what he brought. One day he brought something, and Sayyiduna Abu Bakr (may Allah be pleased with him) ate from it. The slave said to him: Do you know what this was? Sayyiduna Abu Bakr (may Allah be pleased with him) asked: What was it? He said: In the time of Ignorance I had practised soothsaying for a person, though I was not skilled at soothsaying; I only deceived him. That man met me and gave me this, which you have eaten from. Sayyiduna Abu Bakr (may Allah be pleased with him) put his hand (into his mouth) and vomited up everything that was in his stomach.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الغصب / 11527