Praise be to Allah.
Islam does not forbid the Muslim to let his thoughts wander and imagine permissible things, because this is human nature. Allah, may He be glorified and exalted, has created in them a wonderful world of imagination, images and talk that may cross their minds, and a person may not be able to ward them off completely, but he does have the power to control them and guard against those that are harmful.
It is well-known that some of these thoughts that a person may find himself immersed in may turn to some kind of illusion, and lead to mental exhaustion and an inability to focus. Oftentimes that results in a real-life situation filled with frustration and despair, or leads to bad conduct as a result of repeated thoughts, and the individual would not have found himself in that situation if he had restrained his thoughts and prevented them from wandering into that wilderness.
We think that the thoughts that could lead to success are realistic thoughts, in which one plans for a better future, within the framework of what is possible, not what is impossible, and strives to work out practical steps that may lead to success in one’s family life, academic life and social life, through beneficial reading, righteous deeds, and good conduct. If there is no opportunity to achieve such goals, then patience and contentment are two guiding principles that should always be in the mind of the believer.
This is the difference between harmful, bad thoughts and beneficial, realistic thoughts. Young men and women in particular should pay attention to this, and beware of following in the footsteps of the Shaytaan who, by means of thoughts and imagination, opens the door to evil and sin. Sin begins with a thought and ends with regret. If what is meant by imagining emotional life is imagining having intercourse with a particular young man in the hope that he will be one’s husband in the future, this comes under the heading of corrupt thoughts and imagination which bring no benefit and result in nothing but pain, regret and thinking of sin. This has been discussed in detail previously on our website, in the answer to question no. 84066.
Abu Haamid al-Ghazaali (may Allah have mercy on him) said:
It should be understood that the likeness of the heart is that of a target that is struck by arrows from all sides.
Or it is like a mirror in front of which different things pass constantly, and image after image is reflected in it; there is always something reflected in it.
Or it is like a cistern into which water flows from various channels that lead to it.
These constantly-renewed impacts on the heart either come from the outside, through the five senses, or they come from within, through imagination, desire, anger, and attitudes that are instilled in man’s nature. … As one’s thoughts move from one thing to another, the condition of the heart moves from one state to another.
The point is that the heart is always changing and is constantly affected by these causes. The greatest impact on the heart comes from thoughts. Moreover, thoughts lead to desires, and desires lead to resolve, and resolve leads to intention (niyyah), and intention leads to physical action.
Thoughts that lead to desires may be divided into those that motivate one to do evil, and those that motivate one to do good. These are two different types of thoughts. The good thoughts are called inspiration, and the bad thoughts are called waswaas (whispers from the Shaytaan).
End quote from Ihyaa’ ‘Uloom as-Deen (3/26).
And Allah knows best.