Hi.
We don’t need a miracle to believe that the host is true body and blood of Jesus. Either one believes it is so or one does not. It is a matter of faith and belief.
Miracles do happen. It is a complicated thing. So the issue why it happen does not arise; that’s why this subject can be very much misunderstood because we want to know why.
Likewise miracles happen in the Gospels and we can never know exactly why they happened – the multiplication of bread and fish, the healing of the lepers and the blinds, the deliverance of demons and the rising of the deads. Jesus did not say categorically, “I am going to perform this miracle because I want to prove to you …” No, he did not say that.
But sometimes the reason is because he is what he is - compassionate – in many ways. Because of our lack of faith, because of our illness, because we cannot help ourselves but most of all because we need him and sometimes need affirmation that he is with us – all the time.
The Eucharistic miracle can fall into any of the category; it acts differently on different people.
By no means it is only to demonstrate that the host is flesh of Jesus. I doubt very much it is meant to be such though it appears as his flesh. Most of all, he is present there but more so the effect of the miracle is far reaching because it speaks to the Church as a whole. God is with us; he is in the Eucharist in his real self.
We may be Thomas or not but nevertheless he appeared in the upper room all the same. What’s true is that he was experienced individually and they have individual testimony to it.
God bless.