Hadith 31-21

وَبِهذَا الإِسنادِ قالَ: قالَ رَسُولُ اللَّهِ‏ صَلَّى اللهُ عَلَيْهِ وَآلِهِ: لا يَزالُ الشَّيْطانُ ذَعِراً مِنَ المُؤمِنِ ما حافَظَ عَلَى الصَلَواتِ الخَمسِ؛ فَإِذا ضَيَّعَهُنَّ تَجَرَّأَ عَلَيْهِ وَأَوقَعَهُ فِي العَظائِمَ.

According to the same documentation, God’s Prophet (S) said, “As long as a believer guards his prayers Satan fears him. Once he gets negligent about saying his prayers Satan overcomes him and leads him to commit sins.”