Sunan Ibn Majah Book 34, Hadith 22
"A man come to the Prophet (saas) and said: 'O Messenger of Allah, what supplication is best?' He said: 'Ask your Lord for forgiveness and to be kept safe and sound in this world and in the Hereafter.' Then (the man) came the next day and said: 'O Messenger of Allah, what supplication is best?' He said: 'Ask your Lord for forgiveness and to be kept safe and sound in this world and in the Hereafter.' Then (the man) came the third day and said: 'O Prophet of Allah, what supplication is best?' He said: 'Ask your Lord for forgiveness and to be kept safe and sound in this world and in the Hereafter, for if you are forgiven and kept safe and sound in this world and the Hereafter, you will have succeeded.'"
the Messenger of Allah (saas) said to a man: "What do you say during your prayer?" He said: "I recite the Tashah-hud then I ask for Allah for Paradise and see refuge with Him from Hell, but by Allah I do not understand your whispering or the whispering of Mu'adh." He said: "It is concerning them (Paradise and Hell) that we are whispering."
he heard Abu Bakr, when the Prophet (saas) had passed away, saying: "The Messenger of Allah (saas) stood in this place where I am standing, last year." Then Abu Bakr wept, then he said: "You must adhere to the truth, for with it comes righteousness and they both lead to Paradise. And you must beware of lying for with it comes immorality, and they both lead to Hell. Ask Allah for Al-Mu'afah, for no one is given anything after certainty that is better than Mu'afah. Do not envy one another, do not hate one another, do not sever ties with one another, do not turn your backs on one another and be, O slaves of Allah, brothers."