What's the difference between saying.
"I am great and have achieved much."
and
"Thanks to God's gifts, I have achieved much and have become great."
There is actually quite a difference.
A person saying the latter will be inclined to go easy on his fellow-men, knowing that not everyone is given the same gifts and graces.
Whereas a "self-made man" or someone who believes he achieved everything by his own sweat will be harsh on his fellow-men.
That is how you can tell the difference between a proud man and a humble man. They both could have equal material achievements. But the humble man gives all glory to God.
The litmus test: How he treats his fellow man. Does he have compassion, or not?