Charles H. Spurgeon on Psalms 119:106

I have sworn, and I will perform it, that I will keep thy righteous judgments. Under the influence of the clear light of knowledge he had firmly made up his mind, and solemnly declared his resolve in the sight of God. Perhaps mistrusting his own fickle mind, he had pledged himself in sacred form to abide faithful to the determinations and decisions of his God. Whatever path might open before him, he was sworn to follow that only upon which the lamp of the word was shining. The Scriptures are God's judgments, or verdicts, upon great moral questions; these are all righteous, and hence righteous men should be resolved to keep them at all hazards, since it must always be right to do right. Experience shows that the less of covenanting and swearing men formally enter upon the better, and the genius of our Saviour's teaching is against all supererogatory pledging and swearing; and yet under the gospel we ought to feel ourselves as much bound to obey the word of the Lord as if we had taken an oath so to do. The bonds of love are not less sacred than the fetters of law. When a man has vowed he must be careful to "perform it", and when a man has not vowed in so many words to keep the Lord's judgments, yet is he equally bound to do so by obligations which exist apart from any promise on our part, obligations founded in the eternal fitness of things, and confirmed by the abounding goodness of the Lord our God. Will not every believer own that he is under bonds to the redeeming Lord to follow his example, and keep his words? Yes, the vows of the Lord are upon us, especially upon such as have made profession of discipleship, have been baptized into the thrice holy name, have eaten of the consecrated memorials, and have spoken in the name of the Lord Jesus: We are enlisted, and sworn ill, and are bound to be loyal soldiers all through the war. Thus having taken the word into our hearts by a firm resolve to obey it, we have a lamp within our souls as well as in the Book, and our course will be light unto the end.