Question: Does du'a (supplication, prayer) change qadar? What is the meaning of the statement "If Allah has written it, let Him erase it"? Is it also from qadar to will a person to supplicate? What is the length of time that qadar continues to exist? Is it eternal in the past or eternal in the future? Does qadar have a qadar, too?
To start with, one should know qada', qadar, and their kinds. Qadar is Allahu ta'ala's knowing in the eternal past the things that will happen. Qada' is His creating the things existing in qadar when the time comes. That is, qadar is like a payroll. Qada' is like distribution of wages. Allahu ta'ala knows what all people will do, where and how they will die. It is termed qadar. The Qur'an al-karim says (what means):
(Allah knows what they did and what they will do.) [Al-Baqarah 255]
If a movie is screened many times and if a person watching it before says while watching it the third time, "The leading actor will fall off the horse and die," will the performer die because one member of the audience said so, or does he knows it because he watched it before?
The times when the sun will rise and set in a year are calculated and written on charts and timetables. The sun rises and sets at those times written on charts and timetables. However, it does not rise or set at those times as they were written beforehand so. Their having been written does not affect its rising or setting. Likewise, Allahu ta'ala knows what will befall humans, and He wrote it in al-Lawh al-Mahfuz. A Qur'anic verse says:
(Allah knows the place where every living creature stands and where it will be left in the end. All of them are in a clear book [Al-Lawh al-Mahfuz].) [Hud 6]
Qadar is divided into two categories: qadar that may change and qadar that does not change. For example, the appointed time of death that does not change is called ajal al-musamma. It is declared in a Qur'anic verse:
(Death is never late even for a moment, nor does it come before time is up.) [Al-A'raf 34]
A person's lifetime and sustenance (rizq) may change according to his deeds. The Qur'an al-karim says (what means):
(Allah erases what He wishes, and He does not change what He does not wish to. Umm-ul-kitab [al-Lawh al-Mahfuz] is with Him.) [Ar-Ra'd 39]
Umm-ul-kitab is the name of the Divine word, which is eternal. Angels cannot understand it. It is not with time. No one but Allah knows it. It never ceases to exist. As for al-Lawh al-Mahfuz, there are changes in it. Angels see it. A person's lifetime and sustenance may be changed on account of his deeds. The good may be changed into evil and the evil into good. Another Qur'anic verse says:
(Verily, lifetimes of all and the shortening of lifetimes are recorded in the Book.) [Fatir 11]
The qada' and qadar that may change are termed qada al-mu'allaq. If a person does a good deed and his du'a is accepted, qada' can change. It is declared in hadith-i sharifs:
(Nothing can change the qada al-mu'allaq. Only du'a can change it.) [Hakim]
(Qadar does not change by taking precautions or avoiding. But a du'a that is accepted protects one against an approaching catastrophe.) [Tabarani]
(Silat-ur-rahm [upholding the ties of kinship] lengthens one's lifetime.) [Tabarani]
The recording of qadar in al-Lawh al-Mahfuz is qada'. If the disaster predestined for a person is qada' al-mu'allaq and if it had been predestined also that the person would pray, he prays and, when the prayer is accepted, it prevents the disaster. Du'a's repelling the catastrophe is also within qada' and qadar. As an umbrella is a shield against rain, so du'a acts as a shield against disasters.
Ajal al-musamma (time of death that does not change) does not change, but ajal al-qada' (time of death that is conditional) may change. Let us give an example:
Two people came to Hadrat Dawud and complained about each other. Azrail (Angel of Death) 'alaihis-salam came to him and said, "One of these two people has one week before his death. The other's lifetime was over a week ago, but he did not die." When Hadrat Dawud was astonished and asked the reason why, he answered, "The latter had a relative who was offended with him. He visited him and reconciled himself with him. For this reason, Allahu ta'ala decreed to add 20 years to his lifetime.) (The booklet titled Al-Lawh Al-Mahfuz and Umm-ul-kitab)