What is the meaning of Al-Qadaa and Al-Qadar?

The expressions of scholars have differed in defining Al-Qada (Divine Decree) and Al-Qadar (Divine Predestination). Some have defined them together, while others have defined Al-Qadar as Allah's knowledge of what creatures will be like in the future, and Al-Qada as Allah's bringing things into existence according to His knowledge and will. Belief in Al-Qadar encompasses four levels: belief in Allah's ancient knowledge, the recording of that in Al-Lawh Al-Mahfuz (the Preserved Tablet), His encompassing will and all-encompassing power, and His creation of all beings. It is not permissible to delve into Al-Qadar, for it is Allah's secret among His creation, and deep delving into it leads to disappointment and deprivation; rather, one must believe in it. Belief in Al-Qadar does not contradict reliance on Allah and taking means. This creed grants the believer tranquility and reassurance and motivates him to do what benefits him.