My dear brother in humanity, to not use my mind and make it the measure of all things is to become like an animal. I do not wish to go down to that level and live like a beast. The ability to think and reason is what separates man from animals... So I'm so sorry... I can't give that up. If you wish to do so, well.... nobody's stopping you.
I get the feeling I have offended you?
I think you have misunderstood what I was saying. The mind is all we have and in a way it is all we are and if we loose it or regulate it to second place we are no better that animals. However, all human beings seem able to be logical and can rationalise things or events but it is also obvious that our minds, our thinking abilities are limited and it is in the sense that I used the phrase 'tiny' mind.
What surprises me, even shocks me, is how certain you are of your own conclusions reached by your own intellectual processes. On the one hand you accept without question what Mohammed said or did as absolute truth but for everything else you decide what is or is not truth, or a universal truth as you call it - why are you so certain of your own rational powers, I certainly am not of mine?
For example, Socrates, one of the finest thinkers the world has ever seen said "If I have any authority it is based upon the sure notion that I know nothing." On the face of it this sounds absurd but what it is really saying is that if we forget our limitations and close our minds to argument, new knowledge then we are sure to fail. One only has to consider conspiracy theories to see this where scores of people believe in absurdities: vaccines cause autism, aliens have abducted people, the CIA created aids, 9/11 was a Zionist sponsored event, the holocaust is a myth and so on. Indeed once you think you are immune from such things you are in fact showing your susceptibility to them. Let's face it which of us has never been caught out by a sales gimmick of some kind and ended up buying something we did not need or want. It has to be said also that if we believe in God who created the vastness of eternity then pretending we know exactly the mind of God in every circumstance is foolishness in the extreme.
This is why we must treat all knowledge as tentative always allowing that we just might be wrong. In fact this is the scientific default position, being aware that new theories, new explanations, new interpretations or new data might totally undermine what we thought was solid. Of course we try to obtain confirmations, or verifications, for nearly every theory and if we are honest we not only look for things that uphold the theory but also more importantly, events which are incompatible with the theory, that is an event which would have refuted the theory. When we speak of religious things we run into trouble because they are not generally refutable. A theory which is not refutable by any conceivable event is non-scientific. Of course irrefutability is not a virtue of a theory (as people often think) but a vice.
For example, to use one of your examples that Jesus said, as recorded by Matthew "This is my blood of the covenant, which is poured out for many for the forgiveness of sins." Now it is one thing to accept that Jesus said this, indeed I can see no obvious reason to deny it, but the truth of the actual words is unfalsifiable, that is there no way we can show it to be true if it is true and no way to show it to be false if it is false - it really is totally irrelevant whether Matthew or Jesus were known to tell the truth, the statement cannot be tested and cannot be shown to be true or false. In passing I note, and you may correct me if this is wrong, that Mohammed like Jesus never themselves wrote anything down and always it was a scribe or sometimes several scribes and in general as far as I know we know less about their honesty than that of Matthews'.
In the case of Jesus or Mohammed if you can only indicate a statement's truth with corroborating evidence that these men were truthful - in effect you have introduced ad hoc some auxiliary assumption in such a way that it (the theory) escapes refutation. Such a procedure is always possible, but it rescues the theory from refutation only at the price of destroying, or at least greatly lowering, its status.