The greatest miracle in Jesus ministry is not healing and casting out demon, but is this: He knew that Judas Iscariot was a thief, but He appointed him to be a treasurer.
Isn't it unthinkable? He used the failure in Judas' life, intend to turn it into great use! What would you do if you know your classmate is a thief? Will you appoint him to be a treasurer in your class? I often feel thrilled by many testimonies of signs and wonders like casting out demon and dramatic healing, I am still. However, certainly it is a greater miracle to turn somebody's failure into a greater usefulness, despite how foolish he was but knowing how potential one could be in future.
Do you have any great weakness or failure in life? That part of your life probably is a part God wants to use the most for the profit of all. Don't fall into the lie of demon, the opposer (satan) want you to believe in his lie, that that part of your life is a failure, it is not useful at all. The opposer wants you to leave that part of your life become a waste land.
So what is the area in your life, which you think it's "unredeemable"? God wants to use that now!