In the name of Allah, the Beneficent, the Merciful
An important principle in Islam and a foundational legal maxim in Islamic law was stated by As-Suyuti as follows:
الضَّرَر يُزَال
Harm should be removed.
Source: al-Ashbāh wal-Naẓāʼir 1/7
As a general rule, Muslims should not harm other people, especially other Muslims. The only exception to this rule is due to the need for self-defense against aggression or to avert some greater evil, as stated in the following subsidiary legal maxim:
الضَّرَرُ الْأَشَدُّ يُزَالُ بِالضَّرَرِ الْأَخَفِّ
Greater harm can be removed by lesser harm.
Source: Sharḥ Majallat al-Aḥkām 1/54
The Prophet, SallAllahu Alaihi Wa Sallam. decreed this rule as a matter of law and ethics.
Ubaida ibn As-Samit, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, issued a decree:
لاَ ضَرَرَ وَلاَ ضِرَارَ
Do not cause harm or return harm.
Source: Sunan Ibn Mājah 2340, Grade: Hasan
The Prophet, SallAllahu Alaihi Wa Sallam, defined the true Muslim as one who avoids harming other Muslims with his tongue (words) and hand (actions).
Abdullah bin Amr, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
الْمُسْلِمُ مَنْ سَلِمَ الْمُسْلِمُونَ مِنْ لِسَانِهِ وَيَدِهِ
The Muslim is the one from whose tongue and hand the Muslims are safe.
Source: Ṣaḥīḥ al-Bukhārī 10, Grade: Muttafaqun Alayhi
Amr ibn Absah, RadiyAllahu Anhu, reported: A man said, “O Messenger of Allah, what is Islam?” The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
أَنْ تُسْلِمُ قَلْبَكَ لِلَّهِ وَيَسْلُمُ الْمُسْلِمُونَ مِنْ لِسَانِكَ وَيَدِكَ
That you surrender your heart to Allah and that the Muslims are safe from your tongue and hand.
Source: Shu’ab al-Imān 20, Grade: Sahih
We should be particularly careful to protect those within our own community, but the principle is not restricted only to Muslims. Rather, it applies to all humanity and even the animals.
In another narration of this tradition, the Prophet, SallAllahu Alaihi Wa Sallam, said:
الْمُسْلِمُ مَنْ سَلِمَ النَّاسُ مِنْ لِسَانِهِ وَيَدِهِ وَالْمُؤْمِنُ مَنْ أَمِنَهُ النَّاسُ عَلَى دِمَائِهِمْ وَأَمْوَالِهِمْ
The Muslim is the one from whose tongue and hand the people are safe, and the believer is the one who is trusted with the lives and wealth of the people.
Source: Sunan al-Nasā’ī 4998, Grade: Sahih
And in another narration, the Prophet, SallAllahu Alaihi Wa Sallam, said:
الإسلام أفضل مَنْ سَلِمَ النَّاسُ مِنْ لِسَانِهِ وَيَدِهِ
The best Islam belongs to those from whose tongue and hand people are safe.
Source: Musnad Aḥmad 6714, Grade: Sahih
Hasan Al-Basri, may Allah have mercy on him, said:
إِنْ سَرَّكُمْ أَنْ تَسْلَمُوا وَيَسْلَمَ لَكُمْ دِينُكُمْ فَكُفُّوا أَيْدِيَكُمْ عَنْ دِمَاءِ النَّاسِ وَكُفُّوا أَلْسِنَتَكُمْ عَنْ أَعْرَاضِهِمْ وَكُفُّوا بُطُونَكُمْ عَنْ أَمْوَالِهِمْ
If you would be pleased to be safe and for your religion to be safe for you, then restrain your hands from harming the lives of people, restrain your tongues from harming their honor, and restrain your stomachs from consuming their wealth.
Source: Makārim al-Akhlāq lil-Kharā’iṭī 379
It is not permissible in Islam to harm even a small animal like a bird, a dog, or even pig without a just cause for doing so.
Abdullah ibn Umar, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
مَنْ قَتَلَ عُصْفُورًا فَمَا فَوْقَهَا بِغَيْرِ حَقِّهَا سَأَلَ اللَّهُ عَزَّ وَجَلَّ عَنْهَا يَوْمَ الْقِيَامَةِ
If someone kills so much as a sparrow or anything larger without a just cause, then Allah the Exalted will ask him about it on the Day of Resurrection.
Source: Sunan al-Nasā’ī 4445, Grade: Sahih
In another narration, the Prophet, SallAllahu Alaihi Wa Sallam, said:
مَنْ قَتَلَ عُصْفُورًا عَبَثًا عَجَّ إِلَى اللَّهِ عَزَّ وَجَلَّ يَوْمَ الْقِيَامَةِ يَقُولُ يَا رَبِّ إِنَّ فُلَانًا قَتَلَنِي عَبَثًا وَلَمْ يَقْتُلْنِي لِمَنْفَعَةٍ
Whoever kills so much as a sparrow unjustly will have it pleading to Allah on the Day of Resurrection, saying: O Lord, he killed me for no reason, and he did not kill be for any beneficial purpose.
Source: Sunan al-Nasā’ī 4446, Grade: Hasan
Fudayl ibn Iyad, may Allah be pleased with him, said:
وَاللَّهِ مَا يَحِلُّ لَكَ أَنْ تُؤْذِيَ كَلْبًا وَلَا خِنْزِيرًا بِغَيْرِ حَقٍّ فَكَيْفَ تُؤْذِي مُسْلِمًا
By Allah, it is not lawful for you to harm a dog or a pig without a just cause, so how can you harm a Muslim?
Source: Siyar Aʻlām al-Nubalāʼ 8/427
Indeed, a true Muslim must not harm his neighbors at all, whether they are Muslims or non-Muslims, lest he be forbidden from entering Paradise.
Abu Hurairah, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
مَنْ كَانَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الْآخِرِ فَلَا يُؤْذِي جَارَهُ
Whoever believes in Allah and the Last Day, let him not harm his neighbor.
Source: Ṣaḥīḥ al-Bukhārī 6110, Grade: Muttafaqun Alayhi
In another narration, the Prophet, SallAllahu Alaihi Wa Sallam, said:
لَا يَدْخُلُ الْجَنَّةَ مَنْ لَا يَأْمَنُ جَارُهُ بَوَائِقَهُ
He will not enter Paradise whose neighbor is not secure from his evil.
Source: Ṣaḥīḥ Muslim 46, Grade: Sahih
And in another narration, the Prophet, SallAllahu Alaihi Wa Sallam, said:
أَلَا أُخْبِرُكُمْ بِخَيْرِكُمْ مِنْ شَرِّكُمْ خَيْرُكُمْ مَنْ يُرْجَى خَيْرُهُ وَيُؤْمَنُ شَرُّهُ وَشَرُّكُمْ مَنْ لَا يُرْجَى خَيْرُهُ وَلَا يُؤْمَنُ شَرُّهُ
Shall I not tell you what distinguishes the best of you from the worst of you? The best of you are those from whom goodness is expected and people are safe from their evil. The worst of you are those from whom goodness is not expected and people are not safe from their evil.
Source: Sunan al-Tirmidhī 2263, Grade: Sahih
We all understand how harmful evil actions can be, but many of us do not realize that simple words can be just as harmful. A person might speak an evil word for which he will be punished in Hellfire.
Abu Hurairah, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
إِنَّ الْعَبْدَ لَيَتَكَلَّمُ بِالْكَلِمَةِ يَنْزِلُ بِهَا فِي النَّارِ أَبْعَدَ مَا بَيْنَ الْمَشْرِقِ وَالْمَغْرِبِ
Verily, the servant may speak a single word for which he plummets into the Hellfire farther than the distance between East and West.
Source: Ṣaḥīḥ al-Bukhārī 6112, Grade: Muttafaqun Alayhi
In another narration, the Prophet, SallAllahu Alaihi Wa Sallam, said:
وَإِنَّ الرَّجُلَ لَيَزِلُّ عَلَى لِسَانِهِ أَشَدَّ مَا يَزِلُّ عَلَى قَدَمَيْهِ
Verily, a man stumbles due to his tongue more than he stumbles with his two feet.
Source: Shu’b al-Imān 4484, Grade: Hasan
In contrast, protecting people from harm is a virtuous deed in Islam, such that it can be a means of great reward in the Hereafter. Even a simple act such as removing thorns from the road is a good deed that leads to Paradise.
Abu Barza, RadiyAllahu Anhu, reported: I said, “O Messenger of Allah, teach me something that will benefit me.” The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
اعْزِلْ الْأَذَى عَنْ طَرِيقِ الْمُسْلِمِينَ
Remove harmful things from the roads of the Muslims.
Source: Ṣaḥīḥ Muslim 2618, Grade: Sahih
Abu Hurairah, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
لَقَدْ رَأَيْتُ رَجُلاً يَتَقَلَّبُ فِي الْجَنَّةِ فِي شَجَرَةٍ قَطَعَهَا مِنْ ظَهْرِ الطَّرِيقِ كَانَتْ تُؤْذِي النَّاسَ
Verily, I saw a man enjoying himself in Paradise because he cut down a tree in the road that used to harm people.
Source: Ṣaḥīḥ Muslim 1914, Grade: Sahih
In fact, Allah will treat us in the same way that we treated other people. If we harmed others with our hurtful words and evil deeds, then Allah will similarly punish us on the Day of Resurrection.
Abu Sirmah, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
مَنْ ضَارَّ ضَارَّ اللَّهُ بِهِ وَمَنْ شَاقَّ شَاقَّ اللَّهُ عَلَيْهِ
Whoever harms others, then Allah will harm him. Whoever is harsh with others, then Allah will be harsh with him.
Source: Sunan al-Tirmidhī 1940, Grade: Hasan
Thus, the true believers must always treat others the way they would love to be treated, for they will be treated in this manner in the Hereafter.
Abdullah ibn Amr, RadiyAllahu Anhu, reported: The Messenger of Allah, SallAllahu Alaihi Wa Sallam, said:
مَنْ أَحَبَّ أَنْ يُزَحْزَحَ عَنْ النَّارِ وَيَدْخُلَ الْجَنَّةَ فَلْتُدْرِكْهُ مَنِيَّتُهُ وَهُوَ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الْآخِرِ وَيَأْتِي إِلَى النَّاسِ مَا يُحِبُّ أَنْ يُؤْتَى إِلَيْهِ
Whoever would love to be saved from Hellfire and entered into Paradise, then let him die with faith in Allah and the Last Day and let him treat people the way he would love to be treated.
Source: Ṣaḥīḥ Muslim 1844, Grade: Sahih
In sum, one of the fundamental characteristics of Islam and a true Muslim is to protect people from harm and evil. The only case in which it is permitted to harm someone is if it is the only way to prevent an even greater harm and evil. We have to be sure we treat people well, refrain from harming them, and take steps to ensure harm is reduced from the environment and other people.