"...That's what the Lord did say, upon-a Judgement day..."
I guess one of the things that make Religion appeal to many people is the promise of a "higher justice" - a true justice above the laws of your country, the traditions of your culture etc. This is the justice of God, and this justice is always right: God sees all and he knows it was you who did all the work bringing wealth to your family and not your cousin who just dressed well and had the gift of gab, God saw it was your brother and not you who stole the apples that you got a beating for, etc, etc.
This must be extremely appealing to people living in corrupt and oppressive societies (I'm speaking of the Third World here, of course…) - Because in the end we all die - both the President and the beggar out in the street- and then God will pass judgement and we'll see who makes it to heaven.
If you couple that with a belief in the existence of an afterlife in heaven where all is bliss instead of hard work and agonies - then you've got a pretty strong offering.