The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light. Matthew 6:22.
This says, “thine eye,” not some other person's eye. The rich experience that it is our privilege to have, we lose when we expect someone else to do our seeing for us, and guide us in our spiritual experience as if we were blind. We must have a single eye to God's glory, a single and persistent purpose to leave self and the preferences of others out of the question, not asking, “If I take this course, shall I increase my personal possessions, or shall I decrease them?”
Great simplicity must be cherished by those who seek wisdom of God. Then their feet will not slide. “The path of the just is as the shining light, that shineth more and more unto the perfect day. The way of the wicked is as darkness: they know not at what they stumble.” ...
A person who truly loves and fears God, striving with singleness of purpose to do His will, will place body, mind, heart, soul, and strength under service to God. Thus it was with Enoch. He walked with God. His mind was not defiled by an impure, defective eyesight. Those who are determined to make the will of God their own must serve and please God in everything. Then the character will be harmonious and well-balanced, consistent, cheerful, and true.
“But if thine eye be evil,” if you study selfish purposes, and work only to that end, the whole character is defective, the whole body is full of darkness. Such do not look to Jesus. They do not behold His character, and they are not changed into His image. The spiritual vision is defective, and the way from earth to heaven is darkened by the hellish shadow of Satan. So Satan is pleased to have it, for he can lead that person blindfolded to ruin.
“If therefore the light that is in thee be darkness, how great is that darkness!” The conscience is the regulative faculty, and if people allow their conscience to become perverted, they cannot serve God aright. Their object in life shows to the world whether they are Christians or in rebellion against God. Their whole life is a failure. It is distorted and double, and all the faculties are misdirected. The profession may be all right, but the faith is perverted, and this is revealed by the practice, which misleads others. “No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.”—Letter 128, 1897 (Manuscript Releases 13:154, 155).
From Christ Triumphant - Page 64
Christ Triumphant