It is a supernatural work, bringing a supernatural element into human nature. The soul that is yielded to Christ becomes His own fortress, which He holds in a revolted world, and He intends that no authority shall be known in it except His own. In every difficulty He has His way prepared to bring relief. It is faith that connects us with heaven. The Desire of Ages, p. 480.
All true obedience comes from the heart.
It was heart work with Christ. And if we consent, He will so identify Himself with our thoughts and aims, so blend our hearts and minds into conformity to His will, that when obeying Him we shall be but carrying out our own impulses. The will, refined and sanctified, will find its highest delight in doing His service. When we know God as it is our privilege to know Him, our life will be a life of continual obedience. Desire of Ages, p. 670.