Here's what I discovered. "Steadfast" is "camak" in original Hebrew. It means "to lean upon" or to take hold of something. It's resting your self upon or sustaining your self. Being steadfast is indeed such strong medicine during times of wounding or dark circumstances.
"Steadfast" describes you when you don't focus on the darkness or gloom of your life's difficulties. You remain firm even when you're being discouraged by your feelings. You tell your "catastrophizing" thoughts and feelings to "STOP!" You can have confidence that no matter how traumatic your circumstances may be, you stand secure, knowing that God is greater than all your wounds and problems.
So, if you find your self wavering, discouraged, or falling down, back away from the chaos. Find a quiet place, be still, and refocus. Your peace comes from steadfastly trusting and focusing on God.