عَنْ تَمِيمٍ الدَّارِيِّ أَنَّ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ، قَالَ: «الدِّينُ النَّصِيحَةُ» قُلْنَا: لِمَنْ؟ قَالَ: «لِلَّهِ وَلِكِتَابِهِ وَلِرَسُولِهِ وَلِأَئِمَّةِ الْمُسْلِمِينَ وَعَامَّتِهِمْ»
Tameem Ad-Daariiرضي الله عنه) ) narrated that the Prophet (صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ) said: “Religion is to act with sincerity.” We (the companions) said: “To whom?” He (صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ) said: “To Allah, His book, His Prophet, the leaders of the Muslims and the general masses of Muslims’.” (Muslim, Hadeeth No.55, Page 44, Darut Taybah)
This hadeeth explains that the most important attribute and quality that Muslims must have in their lives, is sincerity. This must be present in their speech, actions and all forms of worship.
A Muslim must therefore be sincere, firstly to Allah, by obeying his commandments; to His book by acting upon its injunctions; to His Prophet (صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ) by following and obeying him; to the leaders of the Muslims by being obedient to them, as long as it conforms to Islam; and to all other Muslims by conveying the true message of Islam to them.
In all aspects of religion, one must be sincere and upon this he shall be rewarded.
The great scholar, Mufti Shabeer Ahmad Uthmaanii(رحمة الله عليه) in his explanation of this hadeeth, says: “Every act in which a person does not have sincerity, is not from the Deen (i.e. it will be devoid of any reward and spiritual gain).