“Then Saul gave David his own armor—a bronze helmet and a coat of mail. David put it on, strapped the sword over it, and took a step or two to see what it was like, for he had never worn such things before. “I can’t go in these,” he protested to Saul. “I’m not used to them.” So David took them off again.” (1 Samuel 17:38-39 NLT)
I don’t believe the issue was as much that David wasn’t used to the armor as it was that it wasn’t his armor. David had a call and a purpose to kill the giant but he couldn’t do it wearing someone else’s armor. We are all called to do something significant, but we must not try to do it wearing someone else’s armor. That doesn’t mean that we don’t accept help, advice, and support from others. It means, don’t try to copy someone else’s calling or walk in their calling. You’ve been given a call to accomplish in a unique way, walk in it. David probably would have gotten tripped up and possibly killed himself if would have tried to fight the enemy in armor that didn’t fit him. Be who God has called you to be and don’t try to fit in someone else’s armor.