To Break the Heart of a Believer is a Great Sin
Anyone who harmed a believer, it is a sin that cannot be compared with any other sin. It is even greater than going to the Ka`aba and demolishing it, and demolishing Bayt al-Ma’moor fifteen times. Breaking the heart of a believer is greater than demolishing the House of Allah. (Sunan Abu Majah )
When you do that you are demolishing the heart of the believer, which, according to a hadith, “The heart of a believer is the House of the Lord.” Therefore, that is greater than destroying the walls of the Kaaba, as mentioned in that hadith, isma waylak, “Listen! Woe to you! Lightning is going to strike now; woe to you!”
It means, beware! This is a warning to the one who is hurting believers; that is to Allah (swt) greater than hurting the Kaaba, as there are weak people who, when you break them, there is no way to restore their hearts, but they renovated the Kaaba many times. How can you restore your heart when someone is repeatedly attacking you? That cannot happen until that person comes and you forgive him. If not, there is no way to build your heart up from being harmed. Don’t hate each other, curse each other, shout at each other, backbite each other, and don’t throw bad rumors at each other!
Mawlana Shaykh Hisham Kabbani