Zina includes all kinds of evil: lack of religious commitment, loss of piety, corruption of chivalry, lack of protective jealousy. You will not find any zaani who is pious, or fulfils covenants, or is sincere in speech, or maintains friendships, or has a proper sense of protective jealousy concerning his family.
Treachery, lying, betrayal, lack of modesty, lack of awareness that Allaah is watching, failure to refrain from indulging in haraam, and loss of protective jealousy are all results of zina.
Another result of zina is the wrath of the Lord due to His sacred limits being transgressed and the sanctity of the family being violated. If a man were to do that to some king, he would punish him in the worst manner.
Another result is darkness of the face, and depression and self-hatred, which are obvious to all onlookers.
Another result is darkness of the heart and extinguishing of light from it, which leads to extinguishing of light in the face and darkness therein.
Another result is inevitable poverty. According to a report, Allah says: “I am Allah, Who destroys tyrants and make adulterers poor.”
Another result is loss of respect for the one who does it, so that he becomes insignificant before Allaah and before His slaves.
Another result is that he loses the best of qualities, such as chastity, righteousness and good character, and he acquires the opposite, so that he becomes known as an immoral person, evildoer, adulterer and betrayer.
Another result is that he is no longer regarded as a believer, as it was narrated in al-Saheehayn that the Prophet (saaws) said: “The adulterer at the time when he is committing adultery is not a believer.” So he loses his faith in a general sense, although he does not lose it altogether. Ja’far ibn Muhammad was asked about this hadeeth and he draw a circle on the ground and said: This is the circle of faith. Then he drew another circle outside it and said: This is the circle of Islam. When a person commits zina he goes out of (the former) but he does not go out of (the latter).
Just because a man has a portion of faith, it does not mean that he can be called a believer, just as if a man has a portion of knowledge and fiqh, he cannot be called a scholar or faqeeh, or if he has a portion of courage or generosity he cannot be called courageous or generous. Similarly, he may have a portion of piety but he cannot be called pious, and so on. The correct view is to take this hadeeth as it appears to be and not try to interpret it otherwise. And Allaah knows best.
Another result is that he exposes himself to becoming one of the inhabitants of the oven in which the Prophet (saaws) saw adulterers and adulteresses.
Another result is that he ceases to be tayyib (good), as Allaah described those who are chaste, and instead becomes khabeeth (bad), as Allaah describes those who commit zina, as Allaah says (interpretation of the meaning): “Bad statements are for bad people (or bad women for bad men) and bad people for bad statements (or bad men for bad women). Good statements are for good people (or good women for good men) and good people for good statements (or good men for good women)” [Noor 24:26].
Allaah has forbidden Paradise to everyone who is khabeeth (bad, evil); rather He has made it an abode for the good, and no one but good people will enter it. Allaah says:
“Those whose lives the angels take while they are in a pious state saying (to them): Peace be on you, enter you Paradise because of that (the good) which you used to do (in the world)” [al-Nahl 16:32]
“and its keepers will say: Peace be upon you! You have done well, so enter here to abide therein” [al-Zumar 39:73]
They only deserve the greeting of the angels and admission to Paradise because of their goodness, but zina is one of the most evil of actions, and Allaah has made Hell the abode of evil and evil people. When the Day of Resurrection comes, He will separate evil from good, and He will put evil all together, then throw it and its people into Hell. No good person will enter Hell and no evil person will enter Paradise.
Another result is the sense of alienation which Allaah casts into the heart of the adulterer or fornicator, and it is akin to the alienation that appears in his face. The chaste person has sweetness in his face and comfort in his heart, and the one who sits with him feels comfortable with him. But the adulterer or fornicator has alienation in his face and the one who sits with him feels uncomfortable with him.
Another result is lack of respect from his family, companions and others. He is the least significant of things in their eyes, unlike the chaste man, who is respected and liked.
Another result is that people regard him as treacherous, and no one will trust him with regard to his womenfolk or children.
Another result is the odour that emanates from him and is smelled by everyone who has a sound heart; it comes from his mouth and body.
Another result is anxiety, because adulterers get the opposite of what they seek. The one who seeks the pleasures and good things of life by doing that which Allaah has forbidden will be punished with the opposite of what he sought, because that which is with Allaah can only be attained by obeying Him. Allaah never makes disobedience to Him the means of attaining goodness. If the evildoer understood what pleasure, joy, delight and good living there is in chastity, he would think that what he has missed out on of pleasure is many times greater than that which he has attained, let alone the ultimate achievement of attaining the reward and honour of Allaah.
Another result is that he exposes himself to missing out on the enjoyment of the maidens in delightful abodes in the Paradise of ‘Adn (Garden of Eden). We have stated above that Allaah will punish the one who wears silk in this world by depriving him of wearing it on the Day of Resurrection, and He will punish the one who drinks wine in this world by depriving him of it on the Day of Resurrection. Similarly, in the case of the one who seeks haraam forms of pleasure in this world, for everything that he got in this world, if it was available in a permissible form, his share of it on the Day of Resurrection will be reduced, and whatever he got in haraam ways will be reduced on the Day of Resurrection.
Another result is that adulterer or fornicator leads to severing of family ties, disobedience towards parents, prohibited earnings, wronging people and loss of one’s wife and family, and it may led to shedding of blood that it is not permissible to shed, or seeking help by means of witchcraft and shirk, whether he realizes it or not. This sin can only be committed if it is accompanied by other sins, beforehand or alongside it, and it generates other sins that come after it. It is surrounded by a legion of sins that come before it and after it, and it is the action that brings the most evil in this world and in the Hereafter and prevents the most goodness in this world and in the Hereafter. Once a person falls into the trap of this sin, no advice will benefit him and no one can save him from it, and the blessings of Allaah will soon depart from him. Anyone who commits this sin may bid farewell to the blessings of Allaah.
Allaah says: “That is so because Allaah will never change a grace which He has bestowed on a people until they change what is in their ownselves. And verily, Allaah is All-Hearer, All‑Knower” [al-Anfaal 8:53]
“But when Allaah wills a people’s punishment, there can be no turning back of it, and they will find besides Him no protector” [Raad 13:11]
Ibn Qayyim Rawdat al-Muhibbeen, p. 360-363