Sahih Bukhari Volume 6, Book 60, Hadith Number 151.

Narrated By Abdullah : Allah’s Apostle said, “The key of the Unseen are five: Verily with Allah (Alone) is the knowledge of the Hour He sends down the rain and knows what is in the wombs. No soul knows what it will earn tomorrow, and no soul knows in what land it will die. Verily, Allah is All-Knower, All-Aware.” (31.34)