the guy is singing it in court, just before he is about to be tortured to death for practising islam
its based on the hadith of the prophet, "islam came as a strange religion and will leave as a strange religion, so glad tiding to the strangers" (along those lines)
(skip to about the 45 second mark, thats where it starts)
for those who dont understand, this is a rough translation:
Ghuraba.. war tadaynaha shiaran lilhayah
Strangarers, and we’re happy with the title as a slogan for life.
Ghurabaun wa li gahyrilahi laa nahmil jibaah
Stranges, and to other than Allah we shall not bow to.
Ghurabaaun wartadaynaha shiaran lilhayah
Strangers, and we are happy with the title as a slogan for life.
Intasal anna fainnaa laa nubalil bitughaah
If you ask about us, we are not bothered by (what the tyrants) do to us.
Nahnu jundulahi dawman, darbunal darbul ubaah
We are the soldiers of Allah always, our path is the path of the brave.
We are not bothered by the chains.
Balsanamdi lil khulood
Rather, we shall progress to eternity.
Falnujaahid wa nunaadhil
So let us struggle and compete.
Wa nuqaatil minjadeed
And fight with (renewed) hope.
Ghurabaaun hakatahal ahraarh fee dunyal abeed
Strangers, that’s how free people are like in a world of slaves.
‘strangers, and we have adopted the name for life’
‘strangers…. And it continues…