What is Islam's view on divine decree and destiny (al-Qadaa wal-Qadar), and what is obligatory to believe regarding it?

Belief in Divine Decree (Qada and Qadar) is the firm conviction that everything that occurs in the universe is by Allah's decree. It is the sixth pillar of faith. Belief in Qadar includes believing in its four levels: Allah's eternal knowledge of everything, His inscription of it in the Preserved Tablet (Al-Lawh Al-Mahfuz), His pervasive will, and His creation of everything, including the actions of His servants. The servant has a will and choice that do not transcend Allah's will and power. Belief in Qadar is Allah's secret among His creation, and it is not permissible to delve into it with limited human intellect.