For now consider the board concept “religion” without any specification.
what is religion?
Not all philosophies are religions however every religion should be philosophy. (why?, i will talk about the reason later). I used to consider religion as a kind of transnatural strength. Then follows the question: why do we seek for a transnatural strength? Because we can not solve problems which are not trivial. Human beings are suffering the fear that due to their ignorance. So our ancestor timorously looked for reasons for the bad things (flood, diseases,poverty etc. ) hoping to drive out fear, reduce uncertainty, solve dispute etc. However, it can’t be done without formation of a philosophical system (of course the system should be reasonable logically). That is how religion comes to play. Religion becomes meaningful when it can play a (significant?) role on that. It calms our restlessness and imparts us peace of heart. I very much like the sentence saying: “It typifies the human heart, which, when perfectly placid and clear, reflects the very image of the Deity”.
Since some friends talk about relationship to God often, I think religion can be defined in a less vague way (not a very clear definition though). Assume there exists some God (without specification), religion is the desire to establish a relation to God.
A further question is that how should a “good” religion guide us. mercy? tolerant? of course. anything else? I don’t have clear clue of that now.
About “sinner” in Christian
Intense emotion involves in religion. Among those emotion, however, I believe fear takes larger part than hope. If we see to it more carefully, the later is naïve but real which is a little weird. It may be too abstract. Here is an example. There is Chinese saying: “The newborn calf fears not the tiger.” It is because newborn dose not know the tiger is dangerous.
In Christian, it is taken as the ultimate basis of the moral order that God is the ground of all reality. It is obvious that Christian ethics is predicated on an assumption of human inadequacy. As it is said by Reinhold Niebuhr
The order of human existence is too imperiled by chaos, the goodness of man too corrupted by sin, and the possibilities of man too obscured by natural handicaps, to make human order and human possibilities solid bases of the moral imperative. [from An Interpretation of Christian Ethics]
What should we rely on to save ourselves? humanity or God? According to Christian, only God for sure since he is the one and the only one solution to the equation.