It was narrated that Sa'eed bin Zaid bin 'Amr bin Nufail said:
"The Messenger of Allah was one of the Ten (given glad tidings of Paradise). He said: 'Abu Bakr will be in Paradise; 'Umar will be in Paradise; 'Uthman will be in Paradise; 'Ali will be in Paradise; Talhah will be in Paradise; Zubair will be in Paradise; Sa'd will be in Paradise; 'Abdur-Rahman will be in Paradise." He was asked: 'Who will be the ninth?' He said: 'I will.'" (ID)
English reference (ID): Vol. 1, Book 1, Hadith 133 (ID)
Arabic reference (ID): Book 1, Hadith 138 (ID)