"The disease of the nations before you is creeping towards you: Envy and hatred, it is the Haliqah. I do not speak of what cuts the hair, but what severs the religion. By the One in Whose Hand is my soul! You will not enter Paradise until you believe, and you will not believe until you love each other. Shall I tell you about what will strengthen that for you? Spread the Salam among each other."
Jami` at-Tirmidhi Book 37, Hadith 96
← Previous Hadith "Shall I not inform you of what is more virtuous than the rank of fasting, Salat, and charity?" They said: "But of course!" He said: "Making peace between each other. For indeed spoiling relations with each other is the Haliqah." It has been related that the Prophet SAW said: "It is the Haliqah, I do not speak of what cuts hair, but it severs the religion."

Jami` at-Tirmidhi Book 37, Hadith 95 Next Hadith → "There is no sin more worthy of Allah hastening the punishment upon its practitioner in the world – along with what is in store for him in the Hereafter – than tyranny and severing the ties of kinship.” (Sahih)

Jami` at-Tirmidhi Book 37, Hadith 97