The language he uses is in the utmost degree significant. There is no haste about it, nor is there any exaggeration. It is the expression of the result of a severe and protracted mental and moral training, under the influence of the Spirit of God. "I have _learned_." The lesson has been a difficult one, but I have mastered it. "_I_ have learned." The "I" is emphatic. "Whether others have learned the lesson or not, _I_ have learned it." The apostle does not speak either hesitatingly or slightingly of his attainment. Thus, when he says, "I know both how to be abased, and how to abound," he goes on to use a word which means, literally, "I have been taught the secret," "I have been initiated into the mysteries"--both of satisfaction and of hunger, both of plenty and of want. Such language implies that his contentment was one which had not been easily acquired. He had not passed into it by a single step only. I do not suppose the process was a very slow one, but it _was_ a process. The lesson had to be spelt out, word by word, often syllable by syllable, perhaps sometimes with tearful eyes and a bleeding heart. And so these words are a record of attainment such as this world cannot snatch. The man who could so speak of himself was in possession of the best knowledge. He had graduated and taken honours in the highest university. II. The practical importance of this lesson of contentment must be obvious to all. Two considerations will enable us to see its importance clearly. 1. Our earthly life is a scene of change. No position is secured to any of us in this world, nor is it in the power of any of us to remain always, and safe from molestation, in a coveted state of action, or of existence, or of enjoyment. Some men never get into a state of positive happiness, and, in the experience of many, the transitions from high to low positions are startling, romantic, painful, mysterious. Events which men call accidents are constantly changing the aspects of things, and certainly the most marked characteristic of our life is vicissitude. This is a truth which is known and recognized by all, and possibly it is one which is felt acutely by not a few who are here at this time. 2. The changes to which we are exposed are temptations to disquietude of heart, and consequently to discontent. This is true in a peculiar sense of those who look only to the present world for satisfaction, but it is also true to a certain extent of the Christian. And why? Partly because he is seldom perfectly free from unworldliness of desire and of hope; partly because he does not always read aright the meaning of his discipline, and keep in mind the truth that because it is Divine it must be always wise and good; and partly because he looks too much to "second causes," not only in disappointment and sorrow, but also in success and joy, forgetting the hand and the purpose of God.