Another proof of the conquest of a soul for Christ will be found in a real change of life. If the man does not live differently from what he did before, both at home and abroad, his repentance needs to be repented of, and his conversion is a fiction. Not only action and language, but spirit and temper must be changed... Abiding under the power of any known sin is a mark of our being the servants of sin, for "his servants ye are to whom ye obey." Idle are the boasts of a man who harbors within himself the love of any transgression. He may feel what he likes, and believe what he likes, he is still in the gall of bitterness and the bonds of iniquity while a single sin rules his heart and life. True regeneration implants a hatred of all evil; and where one sin is delighted in, the evidence is fatal to a sound hope...
There must be a harmony between the life and the profession. A Christian professes to renounce sin; and if he does not do so, his name is an imposture.
Charles Spurgeon (1834-1892)