The proof of the Christian is in the living. To other people, the proof of your conversion is not what you say, but what you do. There is another way to test whether or not you have been born again. Not only is your inward self altered, and your outward self too, but the very root and principle of your life just become totally new. While we are unregenerate, our principle is to seek our own pleasure, our own advancement.
Grace changes the principles of a person.
Our inmost self, the deep rocks of our principles upon which the topsoil of our actions rests, the soul of our personhood, is thoroughly changed, and we are new creatures in Christ. The Son of God is not ours to enjoy, to love, to delight in, unless we too are a child of God. If you do not enjoy the spirit of adoption, then do not deceive yourself, this Son is not given to you. If unto us a Son is given, then we are given to the Son. If this Son of God is given to you, you will have consecrated yourself wholly to Him, and you will feel that His honor is your life's object, that His glory is the one great desire of your spirit.