Sahih Muslim
The Book Pertaining to Paradise, Its Description, Its Bounties and Its Intimates (Kitab Al-Jannat wa Sifat Naimiha wa Ahliha)
Book Number: 040 / Hadith Number: 6786
Sahl b. Sa'd reported Allah's Messenger (may peace be upon him) as saying: In Paradise, there is a tree under the shadow of which a rider can travel for a hundred years without covering (the distance) completely. This hadith has also been transmitted on the authority of Abu Sa'id al-Khudri that Allah's Apostle (may peace be upon him) is reported to have said: In Paradise, there is a tree under the shadow of which a rider of a fine and swift-footed horse would travel for a hundred years without covering the distance completely. There would be the pleasure of Allah for the inmates of Paradise and He would never be annoyed with them.