This is the title of the first chapter of Nietzsche's last book Ecce Homo (= Behold the Man). And while its blatant arrogance is probably a consequence of the incipient manic grandiosity of his syphilitic encephalopathy, it does capture the basic conceit of all authors.
By writing anything which we hope or expect others to read, we are implicitly prefacing it with 'Why I am so Wise'.
So, why am I so wise about Christianity that - despite having only been a Christian, and not a good one, for about five or six years, I publish so much on the topic - why should I imagine that I have any claim to attention?
Probably there are only two such claims - the first being that I was a convinced and active atheist until my late forties- so I have clear and detailed memories of why I was not a Christian.
Understanding how it was that these stumbling blocks were eventually overcome may be instructive.
But the other is that - having become a 'Mere' Christian under the influence of C.S Lewis - I approached the various Christian denominations with a positive prejudice, wanting to know the good in them, hoping to agree with them at a fundamental level - and I have largely retaining this positive attitude towards denominations, even as I reject the majority of self-styled Christians as deluded or dishonest.
This is the opposite to how most people approach such matters - most people are negatively prejudiced against other denominations than their own, but tend to be very relaxed and 'inclusive' about the validity of individual people - and will tend to give the benefit of the doubt to anybody who is a self-styled Christian.
I'm not sure why my attitude on this point is so different from that of other people - and while it is probably not superior to the more normal attitude - it does at least have the virtue of providing a different perspective on perennial problems and recurrent debating topics.