Sahih Muslim | Book 35 | Chapter 9

Narrated by Qatada
Qatada asked Anas which Supplication Allah's Apostle (may peace be upon him) frequently made. He said: The supplication that he (the Holy Prophet made very frequently is this: "O Allah, grant us the good in this world and the good in the Hereafter and save us from the torment of Hell-Fire." He (Qatada) said that whenever Anas had to supplicate he made this very supplication, and whenever he (intended) to make another supplication he (inserted) this very supplication in that.

Narrated by Anas
Anas reported that Allah's Messenger (may peace be upon him) used to supplicate (in these words): "Our Lord, grant us the good in this world and the good in the Hereafter and save us from the torment of Hell Fire.