Explanation

The fundamental principle of an Islamic system is Tauheed

Tauheed *(kalma)· ‎لآ اِلَهَ اِلّا اللّهُ مُحَمَّدٌ رَسُوُل اللّهِ“There is none worthy of worship except God (Allah) and Muhammad is the messenger of God.”

****
These five fundamental principles of an Islamic system are of Islam:

1) Shahadatain (Touheed) (Kalmah)