Is the fact that Christians live among Muslims sufficient for the Message to have been conveyed to them?
Praise be to Allaah.
The fact that they are present in a Muslim country means that they will be considered as being among those who have heard the Message of Muhammad (peace and blessings of Allaah be upon him), and the appropriate rulings will apply to them, because Allaah says (interpretation of the meaning):
“… this Qur’aan has been revealed to me that I may therewith warn you and whomsoever it may reach…” [al-An’aam 6:19]
And the Prophet (peace and blessings of Allaah be upon him) said: “By the One in Whose Hand is my soul, no one of this nation, Jew or Christian, will hear of me then die without believing in that with which I have been sent, but he will be one of the people of Hell.” (Narrated by Muslim).