Al-Baqra Verse 26
Surely Allah is not ashamed to set forth any parable-- (that of) a gnat or any thing above that; then as for those who believe, they know that it is the truth from their Lord, and as for those who disbelieve, they say: What is it that Allah means by this parable: He causes many to err by it and many He leads aright by it! but He does not cause to err by it (any) except the transgressors,
(Sahih Bukhari, Volume 3, Book 31, Number 120)
The Prophet (pbuh) said, “There is a gate in Paradise called Ar- Raiyan, and those who observe fasting will enter through it on the Day of Resurrection and none except them will enter through it”.