عن جَابِر بن عبد الله رضي الله عنهما قال: سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ: «بَيْنَ الرَّجُلِ وَبَيْنَ الشِّرْكِ وَالْكُفْرِ تَرْكُ الصَّلَاةِ»
عن جَابِر بن عبد الله رضي الله عنهما قال: سَمِعْتُ النَّبِيَّ ﷺ يَقُولُ: «بَيْنَ الرَّجُلِ وَبَيْنَ الشِّرْكِ وَالْكُفْرِ تَرْكُ الصَّلَاةِ»
Jābir said: I heard the Prophet (peace be upon him) say:
‘What separates a person from disbelief and associating partners with God is negligence of prayer’.
The Prophet (peace be upon him) states clearly that the difference between Islam and unbelief is negligence of prayer. So, a person who does not pray is an unbeliever.