Kitab At-Tauhid (The Oneness of Allah)
CHAPTER No: 53
Saying: "O Allah, forgive me if You wish"
It is reported in As-Sahih (Al-Bukhari) from Abu Hurairah (May Allah be pleased with him) that Allah's Messenger (May the peace and blessing of Allah be upon him) said:
"None of you should say: 'O Allah, forgive me if You wish; O Allah, be Merciful to me if You wish; but he should always appeal to Allah with determination, for nobody can force Allah to do something against His Will."
Muslim reports:
"One should appeal to Allah with firm determination for nothing is too much for, or beyond Allah."
Important issues of the Chapter
1) Forbiddance of making any exclusions in the supplication.
2) The reason for not saying 'If You wish'.
3) The Prophet (May the peace and blessing of Allah be upon him) said to make the appeal with firm determination.
4) Ask whatever you can of Allah.
5) The reason for that (for nothing is too much for, or beyond Him).