What is the ruling on traveling to the lands of disbelief for the purpose of da'wah?

The student : And what about settling there with the intention of da'wah?

The Shaykh : The same answer as before, the same answer as before.
The student : Which one? The earlier one or the previous one?

The Shaykh : Yes, meaning if he judges himself to be protected and that he will not be affected by those atmospheres, then we can say that it is permissible in the path of da'wah. But we see the reality that it is the youth who go to those lands, whereas it is obligatory that the shaykhs go, who are far from the likelihood of... what do we say?

The questioner : Deviation.

The Shaykh : The likelihood of being led astray; and therefore da'wah in reality requires very good study so that we know who those are who call to Allah. They must be protected, married, protected in Islamic morals, and this is mostly guaranteed for the elderly shaykhs.
The student : In any case, Muslims face a reality because there are one billion two hundred million Muslims in the world now, and in America alone, for example, there are six million Muslims. This is a reality. Some of them are Americans who became Muslim, and some are those whose fathers emigrated, or rather, I do not say emigrated, but settled in those lands for the purpose of making a living and for the purpose of trade. Do these groups in the midst of disbelieving societies have a ruling that would allow a person to go to enter into them and with them in da'wah, or teaching, or study, or trade, or establishing them in their Islam, or similar things? Is there a justification for this in reality if a person wanted to go to a country where there are no Muslims, would there be a difference in the ruling, or to a country where there is a Muslim community, and there is a mosque, and there is discipline regarding Islam?

The Shaykh : I am still at my previous statement: the shaykhs in age and knowledge go there.
The student : May Allah reward you and reward you with good.