"But, for a Christian, there are, strictly speaking, no chanc..." — C.S. Lewis quote meaning

But, for a Christian, there are, strictly speaking, no chances. A secret Master of the Ceremonies has been at work. Christ, who said to the disciples "Ye have not chosen me, but I have chosen you," can truly say to every group of Christian friends "You have not chosen one another but I have chosen you for one another." The Friendship is not a reward for our discrimination and good taste in finding one another out. It is the instrument by which God reveals to each the beauties of all the others. They are no greater than the beauties of a thousand other men; by Friendship God opens our eyes to them. They are, like all beauties, derived from Him through the Friendship itself, so that it is His instrument for creating as well as for revealing. At this feast it is He who has spread the board and it is He who has chosen the guests. It is He, we may dare to hope, who sometimes does, and always should, preside. Let us not reckon without our Host.