Praise be to Allah.
The verse to which the questioner referred appears in Soorat an-Nisa’, where Allah, may He be exalted, says (interpretation of the meaning):
“Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allah has certainly fabricated a tremendous sin” [an-Nisa’ 4:48].
What this verse means is that Allah, may He be exalted, does not forgive shirk for the one who dies believing in that without having repented. Whoever meets Allah with any sin other than shirk (associating others with Allah) is subject to the will of Allah: If He wills He will punish him, and if He wills He will forgive him.
Repentance is obligatory for all Muslims according to scholarly consensus. Al-Qurtubi said in at-Tadhkirah (p. 53):
Repentance is obligatory for the believers according to the consensus of the Muslims, because Allah, may He be exalted, says (interpretation of the meaning):
“And turn to Allah in repentance, all of you, O believers, that you might succeed” [an-Noor 24:31]
“O you who have believed, repent to Allah with sincere repentance” [at-Tahreem 66:8].
Some sins have to do with matters between a person and his Lord, and others have to do with the rights of other people. The scholars have stipulated three conditions for sincere repentance from sins having to do with matters between a person and his Lord. They are: giving up the sin, regretting what one has done, and resolving not to go back to that sin.
Ibn ‘Abd al-Barr said in at-Tamheed (15/12): Repentance means giving up that reprehensible action in the sense of intending to give it up and actually doing so; resolving never to go back to it; and regretting what one has done of it in the past. This is the sincere repentance that is accepted, if Allah wills, according to the majority of scholars. End quote.
If this sin has to do with the rights of other people, then a fourth condition is stipulated, which is that one should set the matter straight with the other person in this world, by restoring his rights to him or asking him for forgiveness.
It was narrated that Abu Hurayrah (may Allah be pleased with him) said: The Messenger of Allah (blessings and peace of Allah be upon him) said: “Whoever has wronged his brother with regard to his honour or anything else, let him seek his pardon today, before there will be no dinar or dirham (i.e., on the Day of Resurrection), when if he has any good deeds (to his credit), some of his hasanaat (good deeds) will be taken in proportion to his wrongdoing, and if he has no hasanaat then some of the sayi’aat (bad deeds) of the one whom he wronged will be taken and added to his burden.” Narrated by al-Bukhaari (2449).
Al-Qurtubi said in al-Jaami‘ li Ahkaam al-Qur’an (18/199): If the sin involves wronging other people, then repentance from it cannot be valid unless he also restores their rights and settle the matter, whether it has to do with tangible property or an intangible matter, if he is able to do that.
If he is not able to do that, then he should resolve to restore his rights if he becomes able to do so, at the earliest possible time.
If he harmed one of the Muslims, and that person was not aware of it or did not know where that harm came from, then he should remove that harm from him, then ask him to forgive him and pray for Allah’s forgiveness for him. If he forgives him, then the sin is waived from him.
If he sends someone to ask that for him, and that person who was wronged forgives the one who wronged him – whether he knows who he was or not – that is valid.
If one man mistreats another by scaring him for no reason, or upsetting him, or slapping him, or boxing his ears for no good reason, or striking him with a whip and causing him pain, then he comes to him asking him to forgive him, and regretting what he did, and resolving not to do that again, then he keeps humbling himself before him until the other man relents and forgives him, that sin is waived from him. The same applies if he impugns him or insults him, but does not say anything that would the hadd punishment for slander. End quote.
Islamic teachings place a great emphasis on the rights of other people. It is soundly narrated in Saheeh Muslim (2581) from Abu Hurayrah that the Messenger of Allah (blessings and peace of Allah be upon him) said: “Do you know what bankrupt means?” They said: Among us, the one who is bankrupt is the one who has no money or wealth. He said: “The one who is bankrupt among my ummah is the one who will come on the Day of Resurrection with prayer, fasting and zakaah, but he will come having insulted this one, slandered that one, consumed the wealth of this one, shed the blood of that one and beaten this one. They will each be given from his good deeds, and if his good deeds run out before the scores have been settled, some of their bad deeds will be taken and cast upon him, then he will be thrown into Hell.”
And he (blessings and peace of Allah be upon him) said: “Allah will gather the people” – and he gestured with his hand towards Syria – “naked, barefoot, uncircumcised, destitute.” I said: O Messenger of Allah, what is destitute? He said: “Those who have nothing with them. A caller will call out with a voice that will be heard from afar just as it will be heard from up close: I am the Sovereign, the Judge. None of the people of Paradise should enter Paradise when any of the people of Hell is seeking redress from him for having wronged him, and none of the people of Hell should enter Hell when any of the people of Paradise is seeking redress from him for having wronged him, even for a slap.” I said: How will that be redressed when we will come naked, uncircumcised, destitute? He said: “By means of hasanaat (good deeds) and sayyi’aat (bad deeds).” Narrated by Ahmad in al-Musnad (16042); classed as hasan by al-Albaani in Saheeh at-Targheeb wa’t-Tarheeb (3608).
If someone slandered a Muslim man or woman in this world, and the hadd punishment for slander was not carried out on him, or he repented but did not set the matter straight with the one whom he wronged, the hadd punishment will be carried out on him on the Day of Resurrection. It was narrated that ‘Ikrimah said: A man made some food for Ibn ‘Abbaas (may Allah be pleased with him), and whilst the slave woman was serving them, the man said to her: O zaaniyah! Ibn ‘Abbaas said: Stop! If the hadd punishment [for slandering her] is not carried out on you in this world, it will be carried out on you in the hereafter. Narrated by al-Bukhaari in al-Adab al-Mufrad (331); classed as saheeh by Shaykh al-Albaani in Saheeh al-Adab al-Mufrad (252).
Concerning what is mentioned in the question about the basic principles regarding the rights of other people, they may be summed up in three things: physical wellbeing, wealth and honour. Transgression against a person’s rights in these three matters stems from one of two causes:
1.. Negligence in giving people their rights
2.. Enmity towards the other person.
Shaykh al-Islam Ibn Taymiyah said in Majmoo‘ al-Fataawa (10/373): Wronging another person inevitably earns the doer punishment in this world, so as to restrain people from wronging one another.
It is of two types:
The first type is withholding the rights that are due to them. This is negligence.
The second type is doing that which harms them. This is enmity.
Crimes against physical well-being include everything that Allah has forbidden us to do to another person, starting with a slap and ending with killing; that includes all kinds of wounds and injuries.
Crimes against wealth include withholding obligatory rights, such as maintenance for a wife or child, for example. It also includes transgressions against the wealth of other people, no matter what form that mischief takes.
Crimes against honour include every fault that a Muslim ascribes to his brother, whether that is done by backbiting, reviling, slandering or transgression against his sanctity.
The Prophet (blessings and peace of Allah be upon him) summed it up in the words: “The whole of a Muslim is sacred to another Muslim, his blood, his wealth and his honour.”
Ibn Rajab said in Sharh Hadith Labbayk (p. 106): The wrongdoing that is prohibited may sometimes affect people’s physical well-being, the worst of which is shedding blood; sometimes it affects their wealth, and sometimes it affects their honour.
Hence the Prophet (blessings and peace of Allah be upon him) said in his sermon during the Farewell Pilgrimage: “Your blood, your wealth and your honour are sacred to you, as sacred as this day of yours, in this month of yours, in this land of yours.”
Finally: we advise ourselves and our brothers to repent sincerely and restore people’s rights to them, before there comes a day on which no wealth or sons will avail anyone, except the one who comes to Allah with a sound heart.
And Allah knows best.