You can serve as a foil to someone if you show them to be better than you by contrast. If you can’t dance but your friend Lisa can, you can be a foil to Lisa’s grace. (http://www.vocabulary.com/dictionary/foil)
For the Gospel to demonstrate its true magnificence it needs someone to save who is utterly unable to save themself. We are all the perfect fit.
The Gospel is light to our darkness, hope to our hopelessness, righteousness to our sinfulness, power to our powerlessness, ability to our ineptitude, acceptance to our rejection, wisdom to our folly, and the solution to our problem. It supplies our lack, meets our need, and it answers our questions. It is the strength in our weakness, the constancy in our vissitudes, the order in our chaos, the clarity in our confusion, the joy in our mourning, the peace in our storm, and the substance to our reality.
The Gospel is everything we need, and the Gospel is all we need! The Gospel is Good News, Perfect Theology, Spiritual Reality and Eternal Veracity. Correctly understood, the Gospel is a Person, and that Person is Jesus. He is our Perfect Fit!