Shahādah (testifying that there is no God but Allah and that Muḩammad is the Messenger of Allah).
Shahādah is the first pillar of Islam. It expresses the faith of the heart. The faith refers to that decisive knowledge that begets certainty, firm belief, and total submission to Allah. By testifying that there is no Allah but Allah and that Muḩammad is the Messenger of Allah, a person declares openly to people and to Allah that he willingly and joyfully chooses that religion, strictly adheres to it, and intently follows the leader (Prophet Muḩammad). This Shahādah is not acceptable except with a firm belief in the heart. This entails moral conscience to avoid committing what incurs Allah's punishment. Fear of Allah is a byproduct of understanding Allah's sayings:
“Know that Allah knows what is in your minds; therefore beware of Him, and know that Allah is Forgiving, Forbearing” (Qur’ān, 2:235).
“Allah makes you cautious of (retribution from) Himself; and to Allah is the eventual coming.” (Qur’ān, 3:28)
“Indeed, there is only one Allah; so of Me alone should you be afraid.” (Qur’ān, 16:51)
“But do not fear them, and fear Me if you are believers.” (Qur’ān, 3:175)
It also implies the support of Islam and Muslims against their enemies. This is the essence tawakkul (reliance on Allah), which is based on strong belief in Allah with absolute determination. Allah says,
“Upon Allah then put your trust if you are believers.” (Qur’ān, 5:23);
“If Allah assists you, then there is none that can overcome you, and if He forsakes you, who is there then that can assist you after Him? And on Allah should the believers rely”. (Qur’ān, 3:160)
Faith requires loyalty to brothers in creed and displeasure with the opponents to the truth. Thus, believers' love and hate should be according to what pleases Allah. Besides, they should not be blind followers of immoral or atheist people:
“Had they believed in Allah and the prophet and what was revealed to him, they would not have taken them for allies.” (Qur’ān, 5:81)
The shahādah is a symbol for spiritual meanings with great effects on guiding the entire society.
 Muḩammad El-Ghazāli, “A Hundred Questions on Islam”, Al-Azhar Center for Translation (ACT), 2017, p. 12.