Then the second expedition will be dispatched, and they will ask, ‘Is there anyone among you who saw the Companions of the Messenger of Allah—may Allah bless him and grant him peace?’ They will answer, ‘Yes,’ and victory will be granted to them on his account. Then the third expedition will be dispatched, and it will be said, ‘See whether you can find among you anyone who saw someone who saw the Companions of the Messenger of Allah—may Allah bless him and grant him peace.’ They will answer, ‘Yes.’ Then there will be a fourth expedition, and it will be said, ‘Can you find among you anyone who saw someone who saw the Companions of the Messenger of Allah—may Allah bless him and grant him peace?’ Such a man will be found, and victory will be granted to them on his account.”
Al-Bukhārī’s wording mentions three such occasions (1), as in the first narration. His wording, however, is: “A time will come when a group of people will go on a military campaign.” He uses the same wording for the second and third occasions, and in all three he uses (accompanied). The narrations all mention the Companions, the Successors, and their successors; these (2) are the three generations. The fourth generation is mentioned only in some of them. The mention of the third generation is established through more than one chain of transmission in reports recorded by both al-Bukhārī and Muslim (3).
For example, the two Sahīh collections record that Ibn Mas‘ūd said: The Messenger of Allah—may Allah bless him and grant him peace—said:
“The best of my ummah are the generation nearest to me, then those who follow them, then those who follow them. Then people will come whose testimony precedes their oath and whose oath precedes their testimony” (4).