+I. That a threefold spiritual preparation is needed for effective service of God.+[2] It is generally admitted that some kind of preparation is needed, _e.g.,_ for the ministry of the Gospel; but it is not generally recognised that a merely professional preparation is of no avail whatever. A man may pass through the whole routine of college life, both literary and theological, and yet not be a prophet of the Lord. Such preparation is not merely not enough, it is not even essential. "Schools of the prophets" may exist without sending forth a single prophet, and God calls many prophets who have never been inside a school door. This is true of every kind and form of God's service, _e.g.,_ the Sunday-school, the home, Christian literature. In every case a threefold spiritual preparation is necessary. Without it we may pretend to be God's servants; but the disguise will always be imperfect, and we shall always be betraying what we really are. Even the old blind Isaacs whom we deceive will not be sure about us: we may have on Esau's garments, but we shall never perfectly imitate Esau's voice. What, then, is this preparation? 1. _A vision of God._ Before we can serve God effectively, we must to some extent see Him as He is. In all departments of human activity, knowledge of the person served is essential to perfect service. Those who have never seen an earthly king cannot serve him as those who are in daily intercourse with him; their loyalty is at the most a sentiment, not a constraining power. The biographies of God's most eminent servants in all ages make it plain that the first and indispensable state in preparation for His service is a vision of God Himself--a revelation of His majesty and holiness (vers. 1-4). 2. What a man needs before he can effectively serve God is _a vision of himself._ The great hindrance of such service is self-satisfaction and self-sufficiency. But when a man really sees God as He is, he straightway sees himself as he is (ver. 5). Job's experience (Job xlii. 5, 6) Peter's experience (Luke v. 8). He sees himself to be utterly unfit and unable to serve God, and so attains to the second indispensable qualification for such service (Eph. iii. 8; 1 Cor. xv. 9, &c.) 3. The third thing which a man needs before he can effectively serve God is _participation in God's salvation._ This is a rule that needs to be stated with wisdom. As a matter of fact, God has used the ministry of unconverted men. Such men may be guide-posts, though not guides. How much better to be a guide! How much more useful is a guide! But we cannot thus serve our generation unless we have been made a partaker of God's salvation. By a sanctifying process,--a process involving in some cases terrible pain (vers. 6, 7),--we must have been made "separate from sinners."