It was narrated from 'Awn bin Abi Juhaifah that his father said:
"The Messenger of Allah said: 'Abu Bakr and 'Umar are the leaders of the mature people of Paradise, the first and the last, except for the Prophets and the Messengers.'" (RU)
English reference (RU): Vol. 1, Book 1, Hadith 100 (RU)
Arabic reference (RU): Book 1, Hadith 105 (RU)