Sahih Muslim Book 26, Hadith Number 5414.

Chapter : If a person goes away from the place occupied by him, he has a better right to occupy it after coming back.

Abu Huraira reported Allah’s Messenger (may peace be upon him) as saying: When anyone amongst you stands up, and in the hadith transmitted on the authority of Abu ‘Awina, the words are: “He who stands in his place and (goes away) and then comes back to it, he his the greatest right (to occupy that).