This was the First of the Qur'an revealed

The Beginning of the Prophethood of Muhammad ﷺ and the First of the Qur'an revealed

Imam Ahmad recorded that `A'ishah said: The first thing that began happening with the Messenger of Allah ﷺ from the revelation was dreams that he would see in his sleep that would come true. He would not see any dream except that it would come true just like the (clearness of) the daybreak in the morning. Then seclusion became beloved to him. So, he used to go to the cave of Hira' and devote himself to worship there for a number of nights, and he would bring provisions for that. Then he would return to Khadijah and replenish his provisions for a similar number of nights. This continued until the revelation suddenly came to him while he was in the cave of Hira'. The angel came to him while he was in the cave and said, "Read!" The Messen- ger of Allah said,

Verse [ 4] الَّذِي عَلَّمَ بِالْقَلَمِ (Who imparted knowledge by means of the Pen.) The preceding verse spoke of the creation of man. The current verse speaks of man's education or literacy, because knowledge, as part of education and literacy, distinguishes man from all other animals and creatures, and occupies the position of the crown of creation. There are two means, methods or media through which knowledge is imparted: [ 1] oral or spoken method or by word of mouth; and [ 2] Pen or written method. The command iqra' [ read ] at the beginning of Surah refers to the oral or spoken method. However, the current verse, which speaks more explicitly about imparting knowledge, speaks of the written method of recording and transmitting knowledge from generation to generation.

Pen and Writing: The First and Most Important Means of Transmitting Knowledge