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.'" (ID)
English reference (ID): Vol. 1, Book 1, Hadith 100 (ID)
Arabic reference (ID): Book 1, Hadith 105 (ID)