Abu al-Aswad said: Al-Zubayr bin al-Awwam (may Allah be pleased with him) accepted Islam at the age of eight and emigrated at the age of eighteen. Al-Zubayr's uncle would wrap him in a reed mat, hang him up and smoke him with fire, saying: Return to disbelief! And al-Zubayr would say: I will never disbelieve.
Hadith Referenceالمعجم الكبير للطبراني / العشرة / 238