"so  WOE to  the  worshipers  who are  neglectful  of their  prayers"

[Surat Ma'un ayas 4-5]

Prophet Muhammad has been reported to have said:

"Between  a  man and  unbelief  is  the  nonperformance  of  the  prayer" [reported by muslim]

He also was reported to have said:

"The First of one's works that he shall be called to account for on the Day of Judgement is the prayer. If he performed it well, he will be properous. otherwise, he will be a loser"                                                [reported by al-tirmidhi who said it is authentic but singular]

Prophet Muhammad (Alayhi salaat wsalaam) was said to have said:

 " The First Faces that will turn DARK on the day of judgement are faces of those who neglect prayer. in the hell-fire there is a valley called al-malham that contains serpens. each serpent is as fat as a camel's nech and it's length is equal to the distance covered in a day. then it stings the one who neglects the prayer, the poision boils in his body for 70 years then the flesh is torn out"           (reported by Al-Hakim)