Webster’s dictionary defines faith as “a confident belief in the truth or trustworthiness of a person, idea or thing.” The Hebrew word for faith is aman, which means “to regard as true, to realize, to believe.” Notice that both definitions talk about truth and belief. 
The Hebrew word aman implies the idea of receiving a message from someone – a statement, a warning, a promise or a command. We “aman” by believing the message to be true.
Abraham believed God’s promise to give him a son. Mary believed the angel’s message that she would conceive a child by the Holy Ghost.
Abraham and Mary each stood in that moment holding nothing but the message. Both of them could readily think of many logical and valid reasons to reject the truth of it out of hand. But in that fateful moment, they chose to believe, they chose faith.
the Bible says “Now faith is being sure of what we hope for and certain of what we do not see” (Heb. 11:1).
You know what?
What you did, when you chose to believe, was a holy thing.