Prophet Muhammad (sal Allahu alaihi wa sallam) said: “The similitude of believers in regard to mutual love, affection, fellow-feeling is that of one body; when any limb of it aches, the whole body aches, because of sleeplessness and fever.” [Muslim]
If your finger, foot, or any part of your body is hurting, you cannot sleep. Your body may develop a fever while it tries to neutralize the pathogens in an infected part. When one part of your body is trying to fight the enemy, the whole body invariably gets involved in the process. The Prophet (sal Allahu alaihi wa sallam) described the Ummah as one body!
So if a Muslim anywhere in the world, in the centre of the body or the tips, on the finger or on the toes, is hurting, you should feel the same pain. If you are only concerned about your safety and the safety of your direct family, then there’s something wrong with you. You are not really part of the body. The Prophet (sal Allahu alaihi wa sallam) said that the Ummah is one body: It doesn’t matter that they are split into different political states or that they belong to different Madhahibs/Fiqh, as long as the person is a Muslim they are a part of your body.
Sometimes we look at it as, “Only me and my group are Muslims.” Why? Because he doesn’t follow my Jamaa’h, he’s not following my way? As long as you cannot prove that that Muslim is a Kafir (disbeliever), he is a Muslim. As long as you don’t have evidence that such a person is a Murtad (apostate), he is a Muslim; whether he belongs to the same Madhhab or the same group or the same country or not, makes no difference.
We all talk about the importance of having unity. If having unity means having one group, abandoning all the different Jamaa’ts and getting rid of all of the different Madhahibs, then we’ll all just be copies of each other and that’s an impossible thing to have. The fact that the Ummah is diverse and has these different elements in it, is what makes us strong. If a person running a business just has expertise in one area then eventully that will limit how much business he can get. But if he has people with multiple areas of expertise then the amount of business that they can go after will increase accordingly. What we mean by unity is that even though your approach to Islamic work might be different, the Imam that you follow might be different, you are there to help your brother when your brother is in need; that is unity.