When a person attains realization of truth, his thinking becomes God-oriented. It happens naturally then that he becomes a serious person. One aspect of this seriousness is characterized by the learning of lessons. A number of different words have been used in the Quran to express this. For instance, tazakkur (39:9), itibar (23:21), tawassum (15:75), etc. Similarly, in the Hadith, too, we find such words, as the Prophet once observed: “My silence should be the silence of thinking, my observation should be for learning lessons”. (Musnad al-Shihab al-Qudha’i, Hadith No. 1159)
The realization of faith or truth is, in itself, a thing of this nature. What is realization of faith? That is for man to discover the Creator by pondering upon His creation and finding the unseen world in the seen world. In the words of the Quran, he discovers inner realities through the signs of God. That is to say, over and above external vision he develops the capacity for insight.
Pondering or reflection or deep thinking becomes second nature for the believer. This is effectual everywhere. Having such a temperament makes him remember God continually. Every day, he discovers something which increases his conviction in faith, whereas other people see only the outward realities. The believer, due to his temperament, can see the realities beyond outward appearances. The processes of reflection and contemplation do not require a particular place or solitude. These processes continue at every moment in the minds of the believers. Even amidst a crowd he is engaged in deep thought. (The Quran, 24:37)
Learning lessons is spiritual food for a believer. For the believer, if material food is a source of physical strength, then learning lessons has the position of spiritual food. Without material food, the body cannot be healthy. Similarly, without intellectual food, spirituality cannot develop.
Source: Discovering God