Before the fall Adam and Eve were reflecting God's image, but not to a perfected degree. When man reaches perfection, then no deviation or fall is possible because perfection means unity or union with God in love. Love is the strongest power in the universe. After union with God, it is impossible to separate from this supreme power. The fall occurred before man reached perfection.
Evil always creates disturbances and blocks our effort.
Center upon the Divine Principle and knock off the corners. Satan has golden opportunities exploring the corners of your mind. You will meet Satan at the gate of Heaven. Unless you defeat him you cannot go in. Satan can manifest as a force against the Will of God, or that power which blocks your way to God.