Faith has over seventy branches, the most excellent of which is the declaration that there is no god but Allah, and the humblest of which is the removal of a bone from the road. And modesty is a branch of faith.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الإِيمَانُ بِضْعٌ وَسَبْعُونَ أَفْضَلُهَا قَوْلُ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَدْنَاهَا إِمَاطَةُ الْعَظْمِ عَنِ الطَّرِيقِ وَالْحَيَاءُ شُعْبَةٌ مِنَ الإِيمَانِ  

When the deputation of ‘Abd al-Qais came to the Messenger of Allah (May peace be upon him), he commanded them to believe in Allah. He asked : Do you know what faith in Allah is? They replied : Allah and his Apostle know best. He said: It includes the testimony that there is no god but Allah, and that Muhammad is Allah’s Apostle, the observance of the prayer, the payment of zakat, the fasts of Ramadan, and your giving a fifth of the booty.  

إِنَّ وَفْدَ عَبْدِ الْقَيْسِ لَمَّا قَدِمُوا عَلَى رَسُولِ اللَّهِ ﷺ أَمَرَهُمْ بِالإِيمَانِ بِاللَّهِ قَالَ أَتَدْرُونَ مَا الإِيمَانُ بِاللَّهِ قَالُوا اللَّهُ وَرَسُولُهُ أَعْلَمُ قَالَ شَهَادَةُ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ وَإِقَامُ الصَّلاَةِ وَإِيتَاءُ الزَّكَاةِ وَصَوْمُ رَمَضَانَ وَأَنْ تُعْطُوا الْخُمُسَ مِنَ الْمَغْنَمِ  

Between a servant and unbelief there is the abandonment of prayer.  

قَالَ رَسُولُ اللَّهِ ﷺ بَيْنَ الْعَبْدِ وَبَيْنَ الْكُفْرِ تَرْكُ الصَّلاَةِ