Sunan Ibn Majah Book 34, Hadith 28
Messenger of Allah (saas) said: "No one among you should say: "O Allah, forgive me if You will.' Let him be definite in his asking, and no one can compel Allah."
the Messenger of Allah (saas) said: "It is necessary that you do not become hasty." It was said: "What does being hasty mean, O Messenger of Allah?" He said: "When one says: 'I supplicated to Allah but Allah did not answer me.'"
the Messenger of Allah (saas) said: "The Greatest Name of Allah is in these two Verses: And your Ilah (God) is One Ilah (God - Allah), La Ilaha Illa Huwa (none has the right to be worshipped but He), the Most Gracious, the Most Merciful.' And at the beginning of Surah Al 'Imran."