Volume 9 · Book 90 · Hadith 340
Narrated Qais: We went to pay a visit to Khabbab bin Al-Art and he had got himself branded at seven spots over his body. He said, "If Allah's Apostle had not forbidden us to invoke Allah for death, I would have invoked for it."
— Sahih Bukhari, Volume 9, Book 90: Wishes, Hadith #340