If you join anything to Christ, you can not see him so well

I beg thee, mark also, one reason why thou shouldest not look at anything else, and that is, if thou lookest at anything else thou canst not see Christ so well. “Oh!” thou sayest, “I can see Christ in his mercies.” but thou canst not see him so well there, as if you viewed his person. No man can look at two objects at the same time, and see both distinctly. You may afford a wink for the world, and a wink for Christ; but you cannot give Christ a whole look and a whole eye, and the world half an eye too. I beseech thee, Christian, do not try it. If thou lookest on the world, it will be a speck in thine eye, if thou trustest in anything but him, betwixt two stools thou wilt come to the ground, and a fearful fall wilt thou have. Therefore, Christian, look thou only on him. “He only is my rock and my salvation.”

Charles H. Spurgeon-God Alone the Salvation of His People-A Sermon Delivered On Sabbath Morning, May 18, 1856