Why the Qur'an was not revealed at the same time as the Torah , the Injil , the Psalms were revealed ? The infidels also had such a question. The disbelievers say: Why was not the whole Qur'an revealed to him at once ? This is how I came down. In order to strengthen your heart with it, I have gradually recited it to you at a planned level. (Al-Furqan: 32) Allah Ta'ala says in reply , I have revealed this Qur'an according to the situation and need for 23 long years. So that the hearts of you and the believers may be strengthened, O Prophet, and that they may be memorized beautifully. As stated elsewhere. That is , I have sent down the Qur'an piece by piece , so that you may recite it to the people gradually, and I have revealed it properly. (Surat al-Isra'il: 106) Allah Ta'ala is describing the wisdom of sending down the Qur'an piece by piece so that you can keep your heart steadfast on the religion through the Qur'an. The Prophet (peace and blessings of Allaah be upon him) used to face a lot of difficulties in his da'wah work . Despite all these hardships , he continued his missionary work, even though he wanted people to believe. As a result, Allah Ta'ala used to offer consolation at different times , the hard life of the previous prophets, etc., so that he could easily bear these hardships and persevere in them. There is also much more wisdom. That is to say, he has revealed it with a respite so that if any problem arises, it can be solved. So the Qur'an was sent down gradually ; Not being sent down together cannot be a reason not to believe. That is to say, whatever kind of analogy they may come up with to refute and resist the truth , I will send down to you that which contains the true and complete narration. Then Allah Ta'ala said that He has revealed this Qur'an piece by piece according to the context. So that he can easily understand people. Another purpose of the revelation of the Qur'an in fragments is to make it easier to memorize. Because if the Qur'an is revealed together, it will be difficult to memorize. So Allah Ta'ala has revealed this Qur'an with truth and slowly as required. So that people are easy to understand , easy to contain.