In the Qur’an, it is mentioned that the unbelievers are the people who does not recognise and appreciate the signs of Allah. The significance of a believer is his ability to see those signs and proofs. They know that these are not created in vain; they can realise the power and great art of Allah everywhere and find ways to appraise Him. About such people Allah Almighty says (what means): “Who remember Allah while standing or sitting or [lying] on their sides and give thought to the creation of the heavens and the earth, [saying], ‘Our Lord, You did not create this aimlessly; exalted are You [above such a thing]; then protect us from the punishment of the Fire.’”[Qur’an 3:191] 
Many times in the Qur’an, there are expressions like “will you not take heed?” “...there is a sign for thinking men” which emphasise the importance of pondering on the signs of Allah. Allah has created an endless list of things to be the subjects of pondering. Everything we see and sense is indeed a manifestation and sign of Allah; so all those in heavens and in earth and in between may be a means of pondering for us. Allah says (what means): “He causes to grow for you thereby the crops, olives, palm trees, grapevines, and from all the fruits. Indeed in that is a sign for a people who give thought.” [Qur’an 16: 11] 
Let’s think for a while of one of the items mentioned in the above verse; for instance, the “date-tree, as well known, grows up from a seed out of the earth. From this tiny seed (a seed is not even 1 cm3 in size), an enormous wooden mass of several metres long and hundreds of kilograms of weight, forms. The only thing that seed can use while constituting this great mass is the earth in which it is buried. 
How can a seed know how to constitute a tree? How does it know how to decompose the necessary substances in the soil to form food? How can it predict the required shape and structure? This last question is especially important, because it is not an ordinary wooden piece that emerges out from the seed. The seed develops a complex living organism with roots for assimilating substances from the earth, with veins in itself and with branches that are perfectly organised. A human being has difficulty while drawing even a picture of a tree, but on the other hand a simple seed can produce that extremely complex object using the substances in the soil. 
This observation concludes that a seed is extremely intelligent and wise, even more than us. Or better to say, there is an amazing intelligence in what a seed does. But what is the source of that intelligence? How can it be possible for a seed to have such an intelligence and memory like a computer “chip”? 
The chips are produced by people who have intelligence and knowledge. Just like a seed which is created by Allah with the ability to develop a tree. Every seed on earth is encompassed by Allah and grows within His knowledge. He Almighty says (what means): “Indeed, Allah is the cleaver of grain and date seeds. He brings the living out of the dead and brings the dead out of the living. That is Allah; so how are you deluded?” [Qur’an 6: 95] 
A seed is merely one of the numerous signs that Allah has created in the universe. If men begin to think with not only their minds but also with their hearts, asking the question of ‘why’ and ‘how’ to themselves, they can understand that all the universe is a proof of the existence and power of Allah, the Most Exalted. 
However, the unbelievers cannot understand such things, since they don’t have the ability to “see” this purpose- as the Qur’an expresses (what means): “…They have eyes with which they do not see…” [Qur’an 7: 179] i.e., they do not have the wisdom and comprehension to realise the important reality with their materialistic vision. 
On the other hand, believers are different from this ‘blind’ group, because they realise and accept that the whole universe is created by Allah with a certain aim and wisdom. This belief is the first step of faith. As faith and wisdom, both of which are in parallel, increase, they will start to identify every detail of Allah’s creation. 
One of the things to be done to identify the details of Allah’s Creation is to be careful and observant. Because the ability to see the signs of Allah and not to be “blind” like the unbelievers, require a high concentration. 
Allah Almighty says (what means): “Unquestionably, to Allah belongs whatever is in the heavens and earth. Already He knows that upon which you [stand] and [knows] the Day when they will be returned to Him and He will inform them of what they have done. And Allah is Knowing of all things..” [Qur’an 24: 64] 
“Unquestionably, they are in doubt about the meeting with their Lord. Unquestionably He is, of all things, encompassing.” [Qur’an 41:54]
One should train himself to recognise the signs of Allah and should always keep this in mind. Otherwise, mind will start to wander, jumping from one topic to another, wasting time thinking about useless things. 
Mind is like water; unless it is directed which way to flow, it spreads away, to the places that you would not want it to flow. This is a kind of unconsciousness; you can not control your mind. You cannot focus and concentrate on a subject. Actually, you can not conceive the truth behind the events happening and also can not ever have the competence to interfere in them. On the contrary, your mind gets directed by those events. You are “bewildered” all the time, which is not an attribute of a believer, but the unbelievers, as Allah Almighty Says (what means): “...And he who associates with Allah – it is as though he had fallen from the sky and was snatched by the birds or the wind carried him down into a remote place.”[Qur’an 22: 31] 
Believers, on the other hand, are the ones who direct their minds, try to better perceive Allah, and who try to better serve His religion. The believers are the ones “who turn away from ill speech” [Qur’an 23:3]. They free their minds from any useless thoughts and whenever they realise the appeal of Satan, they rescue themselves just like Allah Almighty Says in the Qur’an (what means): “Indeed, those who fear Allah – when an impulse touches them from Satan, they remember [Him] and at once they have insight.”[Qur’an 7: 201] 
Therefore, the believers should be careful to keep their minds free of useless thoughts and ponder only on useful things that serve them in their life and keep them close to the Mighty Creator.
Article source: http://www.islamweb.net/emainpage/