Musnad Ahmad 1:37

Isma'il ibn Ibrahim narrated to us, from Yunus, from al-Hasan, that Abu Bakr addressed the people and said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "O people, the people have not been given anything better in this world than certainty (yaqin) and well-being (mu'afat), so ask Allah, the Mighty and Majestic, for them both."