The Christian groups have organized da'wah, sending out missionaries to different parts of the world including the Muslim world.
They are converting people in huge numbers to Christianity.
Can Muslims also undertake such missions?
Do we have an equivalent world mosque where we send missionaries?
We don't have any such thing. The question here is that, “Is that the way it should be?”
No, it should not be like that. Actually, we should be the most active in spreading the message. We should have the biggest organizations spreading the word, we have the truth, they have falsehood, and they are working night and day, learning the languages of tribes and clans in different parts of world, just to live among them to carry what they considered to be word of God, to those people with dedication.
For us it’s like ma shaa’ Allaah, "if it happens it happens, if it doesn't it doesn't".
We have Jamaat Tableegh, the biggest da’wah organization in the world, with the largest number of followers. When they have their yearly ijtimaa (conference) in Bangladesh, four million followers gather. At the end of the ijtimaa, they make group dua’ for guidance for the world. The correct method is that you must clean up your house before you invite people into it; that we should not be going out and giving da’wah to non-Muslims without first having corrected the ways of the Muslims in our own house and locality.
So, in spite of having lots of followers, very little is being given to non-Muslims. They have played a good role to invite people to mosques, but da’wah? No. We can't say that their people are doing it in an organized fashion.
Hence, this is part of the challenge and it is actually a reflection of the state of the ummah. We are fragmented in different countries with our own individual anthem and flags and nationalism
It is narrated by Abu Dawud that the Messenger of Allah (ﷺ) said, "He is not one of us who calls for 'asabiyyah, (nationalism) or who fights for 'asabiyyah or who dies for 'asabiyyah." 
Islam is about humanity, the ummah, the whole ummah and that is what hajj is about, that is the message of hajj.
 Abu Dawud , The book of Adab (etiquettes), Hadeeth: 5121< Back to Questions