Practically speaking, our actions and choices either validate or invalidate the profession of our beliefs.
If I claim to love you, and I watch you starve to death while I lavishly feed myself, I invalidate and disprove my claim to have loved you.
Like a real time, ongoing, science experiment, situational variables are constantly brought to bear on the great experiment of your life, (which, in this sense, is the sum of your experiences). The variables and changing circumstances are meant to prove you and to try you. The result of those tests reveals the substance of the initial claim. If saving faith has been authored in my life, in my heart, in the soul of my being, it will be experienced as the result of whatever incited it to action. Meaning, most literally, my faith is something that can be experimented with, producing results, and thus experienced.