Mentally working to make things happen is using human will-power, and whether you are using Bible statements, or statements from the Christian Science textbook, or sports psychology, or voodoo dolls it is the same stuff. If your motive is to do good, that is better than a motive to do evil, but when it leaves the divine will out of the picture, it is pagan, and ultimately dangerous!
Using human will-power in spiritual healing is not possible, like trying to serve both God and mammon. The only correct spiritual healing starts from the premise that God's work is complete and perfect, and ours is to recognize this. This is what was revealed to Mary Baker Eddy as the mode of operation of Jesus Christ. He did not will a disease to go away. He did not plead with his Father God to bail certain people out on his behalf. He did not snap his fingers and do a miracle. He recognized the illegitamacy of the disease, not of God, and in his rarefied consciousness, broke the mesmerism so to speak, was able to outpicture God's will, the subject's wholeness.
The human will-power method leaves the patient with a misconception of God, a material conception, if you will, and down the road he reaches out to God, to feel Him, to hear Him and gets nothing! This is very common among "life-long" Christian Scientists who may have experienced wonderful healing years ago but now come up dry.
Spiritual healing gives us a sense of Emmanuel, or God with us, and motivates us to turn to Him in all our ways with renewed effort. To emphasize the point (emphasis added):
"Hold perpetually this thought, — that it is the spiritual idea, the Holy Ghost and Christ, which enables you to demonstrate, with scientific certainty, the rule of healing, based upon its divine Principle, Love, underlying, overlying, and encompassing all true being." (S&H)
Spiritual healing is not human. It is divine. It is not a practitioner who heals. It is God who heals.