If that had been remembered, two opposite errors would have been avoided. The error that was threatening the Colossian Church, and has haunted the Church in general ever since, was that of fancying Christianity to be merely a system of truth to be believed, a rattling skeleton of abstract dogmas, very many and very dry. An unpractical heterodoxy was their danger. An unpractical orthodoxy is as real a peril. You may swallow all the creeds bodily, you may even find in God's truth the food of very sweet and real feeling: but neither knowing nor feeling is enough. The one all-important question for us is--does our Christianity _work_? It is knowledge of His _will_, which becomes an ever active force in our lives! Any other kind of religious knowledge is windy food; as Paul says, it "puffeth up;" the knowledge which feeds the soul with wholesome nourishment is the knowledge of His _will_. The converse error to that of unpractical knowledge, that of an unintelligent practice, is quite as bad. There is always a class of people, and they are unusually numerous to-day, who profess to attach no importance to Christian doctrines, but to put all the stress on Christian morals. They swear by the "Sermon on the Mount," and are blind to the deep doctrinal basis laid in that "sermon" itself, on which its lofty moral teaching is built. What God hath joined together, let no man put asunder. Why pit the parent against the child? why wrench the blossom from its stem? Knowledge is sound when it moulds conduct. Action is good when it is based on knowledge. The knowledge of God is wholesome when it shapes the life. Morality has a basis which makes it vigorous and permanent when it rests upon the knowledge of His will. Again: Progress in knowledge is the law of the Christian life. There should be a continual advancement in the apprehension of God's will, from that first glimpse which saves, to the mature knowledge which Paul here desires for his friends. The progress does not consist in leaving behind old truths, but in a profounder conception of what is contained in these truths. How differently a Fijian just saved, and a Paul on earth, or a Paul in heaven, look at that verse, "God so loved the world that He gave His only begotten Son"! The truths which are dim to the one, like stars seen through a mist, blaze to the other like the same stars to an eye that has travelled millions of leagues nearer them, and sees them to be suns. The law of the Christian life is continuous increase in the knowledge of the depths that lie in the old truths, and of their far-reaching applications. We are to grow in knowledge of the Christ by coming ever nearer to Him, and learning more of the infinite meaning of our earliest lesson that He is the Son of God who has died for us. The constellations that burn in our nightly sky looked down on Chaldean astronomers, but though these are the same, how much more is known about them at Greenwich than was dreamed at Babylon!