Man is a being whom Allah furnishes with the faculty of thought. Yet, most people do not use this very important faculty as they should. In fact, some people almost never think.
In truth, each person possesses a capacity for thought of which even he himself is unaware. Once man begins to use this capacity, facts he has not been able to realise until that very moment begin to be uncovered for him. The deeper he goes in reflection, the more his capacity to think improves, and this is possible for everyone. One just has to realise that one needs to reflect and then to strive hard.
We did not create the heavens and the earth and everything between them as a game. We did not create them except with truth but most of them do not know it. (Surat ad-Dukhan: 38-39)
Did you suppose that We created you for amusement and that you would not return to Us? (Surat al-Muminun: 115)
Therefore, each person needs to ponder the purpose of creation, first as it concerns him himself, and then as it pertains to everything he sees in the universe and every event he experiences throughout his life. Someone who does not think, will understand the facts only after he dies, when he gives account before Allah, but then it will be too late. Allah says in the Qur'an that on the day of account, everybody will think and see the truth:
That day Hell is produced, that day man will remember; but how will the remembrance help him?
He will say, "Oh! If only I had prepared in advance for this life of mine!" (Surat al-Fajr: 23-24)
The truth can be told to a person in many different ways; it can be shown by the use of details, pieces of evidence and by every means. Yet, if this person does not think over this truth on his own, sincerely and honestly with the purpose of comprehending the truth, all these efforts are useless. For this reason, when the messengers of Allah communicated the message to their people, they told them the truth clearly and then summoned them to think.
While Allah has given us a chance in the life of this world to reflect and derive conclusions from our reflections, to see the truth will bring us great gain in our life in the hereafter. For this reason, Allah has summoned all people, through His prophets and books, to reflect on their creation and on the creation of the universe:
Have they not reflected within themselves? Allah did not create the heavens and the earth and everything between them except with truth and for a fixed term. Yet many people reject the meeting with their Lord. (Surat ar-Rum: 8)
A man who reflects grasps the secrets of Allah's creation, the truth of the life of this world, the existence of hell and paradise, and the inner truth of matters. He gets a deeper understanding of the importance of being a person with whom Allah is pleased, and so he lives religion as is its due, recognises Allah's attributes in everything he sees, and begins to think not according to what the majority of people demand but as Allah commands. As a result, he takes pleasure from beauty much more than others do, and does not suffer distress from baseless misapprehensions and worldly greed.
These are only a few of the beautiful things a person who thinks will gain in the world. The gain in the hereafter of someone who always finds the truth by thinking, is the love, approval, mercy and the paradise of our Lord, which are above everything else.