Anas bin Malik narrated that the Messenger of Allah (peace be upon him) said: “Whoever asks Allah (peace be upon him) Paradise three times, Paradise says: ‘O Allah, admit him into Paradise’, and whoever seeks refuge from the Fire three times, the Fire says: ‘O Allah, save him from the Fire.’”
Jami` at-Tirmidhi, Book 38, Hadith 2772