There is perhaps no virtue more attractive in a man than humility. If pride is the root of all that is evil in a man, humility is the root of all his good. But why is this virtue so powerful?
Properly defined, humility is the virtue by which we know our proper place in creation. In other words, humility is simply the truth. And when we embrace the truth, we embrace God Who is the truth.
To be humble, it is not necessary to strike a pose. We need not pretend that we are inferior to all others. We must simply acknowledge that any good in us has come from God. Again, this is nothing but the truth.
A common mistake is to believe that virtues are somehow opposed to one another, but this is not the case. In fact, all virtues are united. We cannot grow in one virtue without strengthening all the others. Virtues are good, and all that is good in man is a gift from God. Since God cannot change or be contradicted, all of His gifts must serve one common end; they must all be united.
The relationship between truth and humility manifests this fact. One cannot be humble without acknowledging the truth, and one cannot acknowledge the truth without being humble. What can we say of ourselves? Are we humble and true?
TomNaegeleBlogs 
“Properly defined, humility is the virtue by which we know our proper place in creation.”
No wonder this virtue is so rare.
Humility is more than this. Humility is accepting that we do not know everything. Thus, there are many “truths,” that are unknown to someone. There are also truths that are unknowable.
Pride leads a man to say, I am right. Extreme pride leads a man to say I am right, because what I say is from God.
But the fact that we don’t know everything is a truth, right? So it still holds true that humility is simply truth.
I take issue with your last two sentences. It isn’t always pride when a man says I’m right. For example, when arguing with an atheist you could certainly say that you as a believer in God are most definitely right.