"Only through radical reliance on Truth can scientific healing power be realized," Mrs. Eddy writes on page 167 of Science and Health.
God's consciousness as Truth constitutes His strength. In other words, God has all-power He is the all-powerful One because He is Truth, which knows no error to make Him weak. Furthermore, since God is Truth, He can never make a mistake; He can never fail.
Christian Science teaches that man, the image and likeness of Truth, expresses the all-powerful nature of Truth, which is God. Man is as free from error as God is.