The number 4 is a very beautiful number. The word Allah which is the name of Allah Himself has 4 letters. Our Prophet (PBUH)’s own name Muhammad has 4 letters in it. His name Muhammad (PBUH) comes in the Quran 4 times. The leaders of all angels are 4 in number i.e. Hazrat Jibrael (A.S), Hazrat Mikaeel (A.S), Hazrat Israfeel (A.S) and Hazrat Izraeel (A.S). There are 4 Holy Books revealed by Allah i.e. Holy Quran, Zaboor (Psalms), Toraat (Torah) and Injeel (Bible). There are 4 Caliphs of Islam i.e. Hazrat Abu Bakr Siddique (R.A), Hazrat Umar Farooq (R.A), Hazrat Usman Ghani (R.A) and Hazrat Ali (R.A). Hazrat Muhammad (PBUH) had 4 daughters i.e Hazrat Zainab (R.A), Hazrat Ruqqaya (R.A), Hazrat Umme Kulsoom (R.A) and Hazrat Fatimatuz Zahra (R.A). There are 4 Imams of Islam i.e. Imam Malik, Imam Abu Hanifa, Imam Shaafi and Imam Ahmed bin Hanbal Rehmatullah. Human being is also made of 4 components i.e. earth, water, fire and air. (Ameerun Nisa, Attock)