Reference: Siyar A’laam an-Nubalaa – Volume 5, Page 158
Ibn Ishaaq narrated:
I heard Mak.hool say ‘I have travelled the entire earth in search of knowledge.’
Translator’s note: Imaam ath-Thahabee adds that this statement is in terms of the lengths to which he strove to seek knowledge, not actually implying he travelled the entire world!