If we are to believe he is really alive with all that that implies, then we have to believe without proof. And of course that is the only way it could be. If it could be somehow proved, then we would have no choice but to believe. We would lose our freedom not to believe. And in the very moment that we lost that freedom, we would cease to be human beings. Our love of God would have been forced upon us, and love that is forced is of course not love at all. Love must be freely given. Love must live in the freedom not to love; it must take risks. Love must be prepared to suffer even as Jesus on the Cross suffered, and part of that suffering is doubt.
We are children, perhaps, at the very moment when we know that it is as children that God loves us - not because we have deserved his love and not in spite of our undeserving; not because we try and not because we recognize the futility of our trying; but simply because he has chosen to love us. We are children because he is our father; and all of our efforts, fruitful and fruitless, to do good, to speak truth, to understand, are the efforts of children who, for all their precocity, are children still in that before we loved him, he loved us, as children, through Jesus Christ our lord.
Principles are what people have instead of God. To be a Christian means among other things to be willing if necessary to sacrifice even your highest principles for God's or your neighbour's sake the way a Christian pacifist must be willing to pick up a baseball bat if there's no other way to stop a man from savagely beating a child. Jesus didn't forgive his executioners on principle but because in some unimaginable way he was able to love them.'Principle' is an even duller word than 'Religion'.