General behavior of Muslims towards each other: Shake hands and greet each other with the greeting of Islam: As-Salamu `Alaykum wa Rahmat Allahi wa Barakatuh (Allah’s Peace, Mercy, and Blessings be upon you,)
Muslims: Visit each other in times of illness and greet each other when sneezing.
Muslims: Give advice; calling for right and forbiding wrong.
Muslims: Love for others what one loves for oneself, and wish them all that is good.
Muslims: Not to harm each other by word or deed.
This means: “Worship Allah and join none with Him in worship, and do good to parents, kinsfolk, orphans, Al-Masakin (the poor), the neighbor who is near of kin, the neighbor who is a stranger, the companion by your side, the wayfarer (you meet), and those (slaves) whom your right hands possess. Verily, Allah does not like such as are proud and boastful.” (An-Nisa’: 36)
The Messenger of Allah (SAWS) said: “He who believes in Allah and the Last Day should do good to his neighbor.” (Reported by al-Bukhariyy and Muslim)
`A'ishah (RA) narrated: “I said to Allah's Messenger (SAWS): O Messenger of Allah! I have two neighbors, which of them should I send a present? He said: To the one who lives nearer to you.” (Reported by al-Bukhariyy)
Allah's Messenger (SAWS) said: “Gabriel impressed upon me (the kind treatment) towards the neighbor (so much) that I thought as if he would soon confer upon him the (right) of inheritance.” (Reported by al-Bukhariyy and Muslim)
The Prophet (SAWS) said, "He who sleeps sated while his neighbor is hungry beside him and he is aware of that does not believe in my message.“ (Reported by Al-Bazzar)
The Messenger of Allah (SAWS) said: “He who believes in Allah and the Last Day should not harm his neighbor.” (Reported by al-Bukhariyy and Muslim)
A man came asking the Messenger (SAWS), “O Allah’s Messenger, a woman used to offer her prescribed prayers regularly, kept the prescribed fast and gave charity, but she used to hurt her neighbors with her (abusive) tongue.” The Messenger (SAWS) said, “She is in hellfire.” (Reported by Ahmad)
The Messenger of Allah (SAWS) said: “By Allah, he does not believe! By Allah, he does not believe! By Allah, he does not believe! It was said: Who is that Allah's Messenger? He said: That person whose neighbor does not feel safe from his evil.” (Reported by Ahmad)
General behavior of Muslims towards each other: Allah says: ﴿مُحَمَّدٌ رَّسُولُ اللهِ وَالَّذِينَ مَعَهُ أَشِدَّاءُ عَلَى الْكُفَّارِ رُحَمَاءُ بَيْنَهُمْ﴾ [ الفتح : 29]
This means: “Muhammad (SAWS) is the Messenger of Allah, and those who are with him are severe against disbelievers, and merciful among themselves.” (Al-Fath: 29)
Allah says: ﴿وَاعْتَصِمُوا بِحَبْلِ اللهِ جَمِيعاً وَلاَ تَفَرَّقُوا﴾ [ آل عمران : 103]
This means: “And hold fast, all of you together, to the Rope of Allah (i.e. this Qur'an), and be not divided among yourselves.” (Al-`Imran: 103)
This means: “So fear Allah and adjust all matters of difference among you.” (Al-Anfal: 1)
The Messenger of Allah (SAWS) said: “On the Day of Resurrection, Allah, the Exalted, will say: Where are those who have mutual love for My Glory's sake? Today, I shall shelter them in My shade when there is no shade but Mine.” (Reported by Muslim)
Greeting each other: The Messenger of Allah (SAWS) said: “Two Muslims will not meet and shake hands without having their sins forgiven (by Allah) before they depart.” (Reported by Abu-Dawud)
The Messenger (SAWS) said: “If one starts talking before greeting (you), do not answer him until he starts greeting before talking.” (Reported by al-Bukhariyy and Muslim)
The Prophet (SAWS) said, "Whoever possesses the following three will possess faith: fairness (even if it is) against your interest, greeting people (whom you know and you do not know) and spending inspite of scantiness.“ (Reported by Al-Bukhariyy)
The visit in the time of illness: The Messenger of Allah (SAWS) said: “Every Muslim has five rights over another Muslim (i.e., he has to perform five duties for another Muslim):
to return the greetings, to visit the sick, to accompany funeral processions, to accept an invitation, to respond to the sneezer [i.e., to say: Yarhamuka Allah (may Allah bestow His Mercy upon you), when the sneezer praises Allah].” (Al-Bukhariyy and Muslim)
The Prophet (SAWS) said: “The rights of the Muslim on his brother Muslim are six: When you meet him, greet him; when he calls upon you, respond to him; when he seeks counsel, give him advice; when he sneezes and praises Allah, say to him: May Allah have mercy upon you; when he is sick, visit him; and when he dies, follow his funeral.” (Reported by Muslim)
Al-Bara’ Ibn `Azib (RA) narrated: “Allah's Messenger (SAWS) commanded us to do seven things and forbade us to do seven (things). He commanded us to visit the sick, follow the funeral procession, answer the sneezer, fulfill the vow, help the oppressed, accept the invitation and greet everyone.” (Reported by al-Bukhariyy and Muslim)
The Messenger of Allah (SAWS) said: “Visit the sick, feed the hungry, and (arrange for the) release of the captive.” (Reported by al-Bukhariyy)
Love: The Prophet (SAWS) said: “None amongst you is a truthful believer until he likes for his brother (fellow Muslim) which he loves for himself.” (Reported by al-Bukhariyy and Muslim)
The Prophet (SAWS) said: “Do not hanker after what others rave. Do not be jealous of one another and do not nurse enmity against others. Do not severe ties with one another. Be fellow brothers, servants of Allah, as He commanded.” (Reported by al-Bukhariyy and Muslim)
Not to harm each other by words or deeds: The Prophet (SAWS) said: “Every (of these three things) of a Muslim are (sacred, and thus) inviolable by another Muslim: his honor, blood and property.” (Reported by Muslim)
The Prophet (SAWS) said: “It is not lawful for a Muslim to terrify another Muslim.” (Reported by Abu-Dawud)
Allah's Messenger (SAWS) said: “It is not lawful for a Muslim to severe relations with his Muslim brother beyond three nights. They (may) meet while one turning one way and the other turning to the other way when they meet. The best of the two is the one who is the first to give greeting.” (Reported by al-Bukhariyy and Muslim)
Vindicate and do not disappoint each other: The Messenger of Allah (SAWS) said: “Support your brother whether he is an oppressor or an oppressed. A man inquired: O Messenger of Allah! I may help him when he is oppressed, but how can I help him when he commits an oppression? He said: You prevent him from committing oppression. That will be your help to him.” (Reported by al-Bukhariyy)
The Prophet (SAWS) said: “Shall I not inform you of something more excellent in degree than fasting, prayer and almsgiving (Sadaqah)? The people replied: Yes, Prophet of Allah! He said: It is putting things right between people, spoiling this (putting things right) is the shaver (i.e. destroys and removes one’s faith and religion).” (Reported by at-Tirmidhiyy)
Help: The Messenger of Allah (SAWS) said: “The believers in their mutual kindness, compassion, and sympathy are like the body. If one of the organs is afflicted, the whole body responds to it with wakefulness and fever.” (Reported by al-Bukhariyy and Muslim)
The Messenger of Allah (SAWS) said: “The one who removes the suffering of a believer out of the sufferings of this worldly life, Allah will relieve him from one of the sufferings of the Day of Resurrection.
And the one who pares way for someone who is insolvent, Allah will make things easy for him in the world and in the Hereafter, and the one who veils the faults of a Muslim, Allah will veil his faults in the world and in the Hereafter. Allah supports His servant as long as the servant backs his brother.” (Reported by Muslim)
The Prophet (SAWS) said: “No (Muslim) man will desert a man who is a Muslim in a place where his respect may be violated and his honor aspersed without Allah deserting him in a place where he wishes His help; and no (Muslim) man who will help a Muslim in a place where his honor may be aspersed and his respect violated without Allah helping him in a place where he wishes His help.” (Reported by Abu-Dawud)
The Prophet (SAWS) said: “If you make intercession, you will be rewarded.” (Reported by al-Bukhariyy and Muslim)