Fundamental beliefs ko Usul al-Deen kehte hain, yani Religion ke jaden. Usul al-Deen paanch hain. Woh hain:
Usul al-Deen (Roots of Religion)
1. Tawhid
Sirf aik Allah hai - Abadi, Khud-Mukhtar; uska koi aghaz ya anjaam nahi hai; woh har cheez par qudrat rakhta hai aur har mamle par hukumat karta hai; woh har cheez ko janta hai, usse kuch bhi chhupa nahi hai. Uski apni marzi har mamle mein hai, woh zabardasti kuch bhi nahi karta. Woh har cheez ko dekhne wala, sunne wala aur har jagah mojood hai, uski koi shakhsiyat nahi hai.
2. 'Adalah, Allah Ki Insaaf
Allah insaafwala hai; woh kisi par zulm nahi karta. Usne hukum diya hai ke hum apne apas me aik dusre ke sath insaaf karein - lekin woh khud hum par sirf insaaf nahi, balki mehr-o-karam ke sath bartaav karta hai. Usne humein apne ibadat ke liye paida kiya hai, taaki hum iske zariye rohani kamal tak pahunchein. Yeh rohani kamal humein Allah ke qareeb pahunchata hai.
3. Nubuwwat
Humain Seedha Raasta dikhane ke liye, Allah ne apne Rasool ko insano ke paas bhejna shuru kiya. Unhe Nabi (Prophet) aur Rasul (messenger) kehte hain. (Jama: Anbiya'; Rusul ya Mursaleen).
4. Imamat
Logon ko Seedha Raasta dikhane ke liye aur Islam ki hifazati maqsad ke liye, Allah ne Hazrat Ali ibn Abi Talib ke baad 11 imamon ko apne Rasool ka waris aur ma'loomatgar muqarrar kiya. Unhe Imams kehte hain. Imam lafzi tor par leader ka matlab hai.
5. Qiyamat
Iske baad Qiyamat aayegi, qayamat ka din. Sab log mar jayenge; phir poora insaniyat qayamat ke liye phir se zinda ki jayegi, apne iman aur amal ka hisaab dene ke liye. Sahih aqeedah rakhne wale aur nek amal karne wale Jannat mein daale jayenge; jabke galat aqeedah rakhne wale Jahannam mein chale jayenge.