Believe in Allah, and His Messenger, and the Book (Surah An-Nisa' 4: 136)

The Order to Have Faith after Believing

Allah commands His faithful servants to adhere to all the elements of faith, its branches, pillars and cornerstones. This is not stated as mere redundancy, but from the view of completing faith and the continual maintenance of it. For instance, the believer proclaims in every prayer,

Guide us to the straight way. (Surah Al-Fatihah 1:6) which means, make us aware of the straight path and increase us in guidance and strengthen us on it. In this Ayah [4:136], Allah commands the believers to believe in Him and in His Messenger, just as He said elsewhere,

O you who believe! Have Taqwa of Allah, and believe in His Messenger, (Surah Al-Hadid 57: 28) Allah's statement,

and the Book which He has sent down to His Messenger, refers to the Qur'an, while,

and the Scripture which He sent down to those before (him); refers to the previously revealed divine Books. Allah then said,

and whosoever disbelieves in Allah, His Angels, His Books, His Messengers, and the Last Day, then indeed he has strayed far away
 meaning, he will have deviated from the correct guidance and strayed far away from its path.



Source: Tafsir ibn Kathir (Abridged)