"It is He Who has sent His Messenger with guidance and the religion of truth, to manifest it over all religion, even though the polytheists dislike it." Al-Hasan's interpretation: So that all religions submit to it, and it governs over the people of all religions. Ibn Abbas's interpretation: So that the Prophet is manifest over all religion, over all the laws of Islam. The Messenger of Allah did not pass away until Allah had completed that for him.
Yahya [narrated] from Abd al-Rahman ibn Yazid, from Sulaym ibn Amir al-Kala'i, who said: I heard al-Miqdad ibn al-Aswad saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "There will not remain any household of mud-brick or hair-tent except that Allah will cause Islam to enter it, through the honor of an honorable one or the humiliation of a humiliated one; either He honors them and makes them of its people, or He humiliates them and they submit to it."
Tafsir of Surat al-Saff, verses 10 through 13.