I. There is no better test of men's progress than the advancing power to do without the things which used to be essential to their lives. The lives of men who have been always growing are strewed along their whole course with things they have learned to do without. From the time when the child casts his leading strings aside, because his legs are strong enough to carry him alone, the growing man goes on for ever leaving each help for a higher, until at last, in that great change to which Isaiah's words seem to apply, he can do without sun and moon as he enters into the immediate presence and essential life of God. And if every progress in life is a change from some new boyhood to some yet riper manhood, if every man is a child to his own possible maturer self, may it not be truly stated that all the spiritual advances of life are advances from some symbol to its reality, and that the abandoned interests and occupations which strew the path which we have travelled are the symbols which we have cast away easily, because we had grasped the realities for which they stood?
II. You may ask (1) How can I tell the symbol from the reality, and so know what things it is good to hold less and less, what things it is good to hold more and more indispensable? The answer no doubt lies in a certain feeling of spirituality and infiniteness and eternity, which belongs to those things which it is good for a man not to be able to do without. (2) When I know what things I must not allow to become indispensable to me, what shall I do then? Shall I throw all those things away? No, certainly not. Not to give up the symbol, but to hold it as a symbol, with that looser grasp which lets its inner reality escape into us, and at the same time makes us always ready to let it go when the reality shall have wholly opened from it, that is the true duty of the Christian as concerns the innocent things of the world. (3) How shall I come to count nothing indispensable but what I really ought to, what I really cannot do without? The answer to that question is in Christ, who holds the answers of all our questions for us. Jesus lifted His disciples past one conception of necessity after another, until at last they knew nothing that was absolutely necessary except God. They began as fishermen, who could not do without their nets, and boats, and houses, and fishing friends, and sports, and gains, and gossipings. He carried them up till they were crying, "Lord, show us the Father, and it sufficeth us."
Phillips Brooks, Sermons,p. 282.
References: Isaiah 60:19. A. B. Bruce, Expository1st series, vol. x., p. 433; Preacher's Monthly,vol. vii, p. 25.Isaiah 60:20. Spurgeon, Sermons,vol. xx., No. 1176. Isaiah 60:22. G. Cousins, Christian World Pulpit,vol. xxviii., p. 9; J. Keble, Sermons for Christmas and Epiphany,p. 299.