His essay is “The Narcissism of ‘Solitary Religion.’” Here’s part of what he says:

There is, I suppose, a sort of paradox here, but it is a very natural one. Faith is something that no one else can do for you. It must be your own faith, or it isn’t faith at all in the proper sense. You can no more have faith by proxy than you can be born by proxy. You can take a degree in absentia, but you cannot take part in faith that way. But when you are born you are normally born into a family. It is like that with faith. The faith is your own, but it immediately admits you to the household of faith. So the Church is not patting itself on the back, or trying to keep itself going, when it says to anyone who professes faith in Christ: you must be a member of a Church and take advantage of the fellowship and the means of grace that the Church affords.