Musnad Ahmad 27:318

Waki' narrated to us, Sufyan narrated to us, from Abdullah ibn Dinar, from Ibn Umar, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The keys of the Unseen are five; no one knows them except Allah: 'Verily, Allah, with Him (alone) is the knowledge of the Hour, He sends down the rain, and knows that which is in the wombs. No person knows what he will earn tomorrow, and no person knows in what land he will die. Verily, Allah is All-Knower, All-Aware.'" [Luqman: 34]