Even if remotely speaking, God did not exist--as so many writers are writing million sellers about these days--those of us who do believe in him would be like God, in his stead. We would be his ambassadors regardless of whether he really were out there or not. We need for him to be out there. We need for him to be here with us. Our lives have more meaning, greater beauty, and hope, if we believe and live as though there is a God.
There may well be a God, but we will never know for sure in this life. Most of us will die with that belief. But, oh, what beautiful lives we will have lived with that belief intact. That sounds like a strange kind of belief. When we read difficult texts in the bible or come across arguments against God's existence that you have to leave unanswered and "live by faith", in a way, we are doing just that, living as though God does exist. When you are kind to someone who is unkind to you, you are strengthening the reality of God. Why else behave in so selfless a manner, if it wasn't because you wanted to emulate God?
Humanity needs a perfect being with no beginning and no end. A creator, a friend, a co-traveler in life's sometimes difficult journey. Humanity needs to believe and emulate such a perfect and loving being, to offset the negative, imperfect and evil tendencies he sometimes sees inside his own heart and in those of others.
If sometimes the universe seems like an unfriendly and lonely place, with all kinds of imperfections and horrors, how much more in such an unacceptable place like our universe, is a belief in God necessary and useful. Perhaps we're here--those of us who believe in God--to carry on a hope of a belief in God whether he exists or not. Some say that God is silent and has been silent for a very long time. Be that as it may, we can carry on a belief in the ideal of God and become a much as possible like the being we call God.
Some will ask you why go through so much trouble. If you have no proof that God exits, why live as though he does? God, or the ideal of God, is the very best that humanity has ever been able to imagine about their origins and about themselves. How much better to live towards the ideal of a being like God, who loves in spite of sometimes not being loved back, instead of living without the awareness of God. Some have said that we should try to reflect God's attributes and thereby others can see God in us. In a way, we become God's ambassadors.
When you read conservative accounts of difficult verses in the Bible or when you experience or see others experiencing difficult situations, if you are a person of faith you gloss over the inconsistencies or lack of information regarding particulars, because you know you must in order to continue believing in God. You want to continue to believe in God because life without a belief in him wouldn't be the same quality of life as you've come to expect for yourself and for those you love.
When people of faith meet together in church or in groups of two, or even when a solitary believer gets down on his knees to pray and meditate on God and learn more about him, in a way they do so because there is no other way to keep alive the reality of God. When you read the Bible or other religious literature you do so to continue the habit and practice of making God more and more real by focusing your attention on him.