Qadar is Allah’s knowing of everything in pre-eternity, what happened and what will happen whether good or bad from pre-eternity to past eternity, their time, place and characteristics, and His ordaining and determining them.

Qada is His creation of things and events when their time is due based on His pre-eternal knowledge and ordaining.

Allah created the whole universe and everything in it – whether living or non-living – based on a program. Allah knows everything that will happen in the universe, He also knows the actions of the tiniest particle in detail. His knowledge covers everything.   

The unique system and wonderful order seen in the universe shows that Allah planned it knowingly and that he creates everything based on that plan when their time is due.

The program that Allah made before He created the universe in pre-eternity is called qadar. His application of that program when its time is due is called  qada.

Then, belief in qada and qadar means to believe without doubt that Allah knows everything, that He programmed everything in pre-eternity and that He creates things and events based on that knowledge and program when their time is due.