"The statutes of the Lord are right, rejoicing the heart--the commandment of the Lord is pure, enlightening the eyes." Psalm 19:8
As without a revelation of the doctrine of salvation we would not know how a sinner could be saved, and thus could not glorify God by our faith; so without a revelation of the precept we would not know how to serve God, and thus could not glorify him by our obedience. Look at this point, believing child of God. You long to glorify God in your body and in your spirit, which are his (1 Cor. 6:20). You desire, whether you eat or drink, or whatever you do, to do all to the glory of God (1 Cor. 10:31). There are times and seasons with you when you sigh and mourn over your barren, unprofitable heart and life, and earnestly long to think and speak and act to his honor and glory who has done so much for you in providence and grace. At least, if you have no such desires you are no Christian, and are at the best but a poor, worldly, dead professor.
When, then, and how far do you live to God's glory? Only then, and only so far as your life, and walk, and conduct harmonize with, and are guided by the precepts of the word. For see the connection. We can only glorify God outwardly by doing his will; we can only know that will, as regards our practical obedience to it, by the express revelation which he has given of it. Where is that revelation? In his word, and chiefly in the preceptive part of it. It is this which makes it "a lamp unto our feet, and a light unto our path." David therefore cried--"Order my steps in your word;" "Make me to go in the path of your commandments;" "O that my ways were directed to keep your statutes!" as feeling that it was only by walking in the word and by the word that he could please God and live to his praise.
We find thousands in this land who, as they think, are doing God service by plans and schemes of their own devising, priding themselves on their good works. But we may say of all these their duties and doings what Augustine said of the ancient Roman virtues, that they are but "splendid sins", or, to use the language of the Church of England, entitled, Works before justification, "for that they are not done as God has willed and commanded them to be done, we doubt not but they have the nature of sin."