Shall I enter Paradise in case I say the obligatory prayers, observe the (fasts) of Ramadan and treat that as lawful which has been made permissible (by the Shari'ah) and deny myself that what is forbidden, and make no addition to it? He (the Holy Prophet) replied in the affirmative. He (the inquirer) said: By Allah, I would add nothing to it.  

أَنَّ رَجُلاً سَأَلَ رَسُولَ اللَّهِ ﷺ فَقَالَ: أَرَأَيْتَ إِذَا صَلَّيْتُ الصَّلَوَاتِ الْمَكْتُوبَاتِ، وَصُمْتُ رَمَضَانَ، وَأَحْلَلْتُ الْحَلاَلَ، وَحَرَّمْتُ الْحَرَامَ، وَلَمْ أَزِدْ عَلَى ذَلِكَ شَيْئًا أَأَدْخُلُ الْجَنَّةَ؟ قَالَ: «نَعَمْ۔» قَالَ: وَاللَّهِ لاَ أَزِيدُ عَلَى ذَلِكَ شَيْئًا۔