Only as we trust the light do we see the light. Unless you and I put our confidence in Jesus Christ, the Son of God and Son of Man, we have no adequate knowledge of Him and no clear vision of Him. We must know that we may love; but we must love that we may know. We must believe that we may see. True, we must see that we may believe, but the preliminary vision which precedes belief is slight and dim as compared with the solidity and the depth of assurance with which we apprehend the reality and know the lustre of Him whom our faith has grasped. You will never know the glory of the light, nor the sweetness with which it falls upon the gazing eye, until you turn your face to that Master, and so receive on your susceptible and waiting heart the warmth and the radiance which He only can bestow. 'Believe in the light.' Trust it; or rather, trust Him who is it. He cannot deceive. This light from heaven can never lead astray. Absolutely we may rely upon it; unconditionally we must follow it. Lean upon Him—to take another metaphor—with all your weight. His arm is strong to bear the burden of our weaknesses, sorrows, and, above all, our sins. 'While ye have light, trust the light.'
But then that is not enough. Man, with his double relations, must have an active and external as well as an inward and contemplative life. And so our Lord, side by side with the exhortation on which I have been touching, puts the other one, 'Walk in the light.' Our inward emotions, however deep and precious, however real the affiance, however whole-hearted the love, are maimed and stunted, and not what the light requires, unless there follows upon them the activity of the walk. What do we get the daylight for? To sit and gaze at it? By no means; but that it may guide us upon our path and help us in all our work. And so all Christian people need ever to remember that Jesus Christ has indissolubly bound together these two phases of our relation to Him as the light of life-inward and blessed contemplation by faith and outward practical activity. To walk is, of course, the familiar metaphor for the external life of man, and all our deeds are to be in conformity with the Light, and in communion with Him. This is the deepest designation, perhaps, of the true character of a Christian life in its external aspect—that it walks in Christ, doing nothing but as His light shines, and ever bearing along with it conscious fellowship with Him who is thus the guiding and irradiating and gladdening and sanctifying life of our lives, '_Walk_ in the light as He _is_ in the light.' Our days fleet and change; His are stable and the same. For, although these words which I have quoted, in their original application refer to God the Father, they are no less true about Him who rests at the right hand of God, and is one light with Him. He _is_ in the light. We may approximate to that stable and calm radiance, even though our lives are passed through changing scenes, and effort and struggle are their characteristics. And oh! how blessed, brother, such a life will be, all gladdened by the unsetting and unclouded sunshine that even in the shadiest places shines, and turns the darkness of the valley of the shadow of death into solemn light; teaching gloom to glow with a hidden sun!
But there is not only the idea of activity here, there is the further notion of progress. Unless Christian people to their faith add work, and have both their faith and their consequent work in a continual condition of progress and growth, there is little reason to believe that they apprehend the light at all. If you trust the light you will walk in it; and if your days are not in conformity nor in communion with Him, and are not advancing nearer and nearer to the central blaze, then it becomes you to ask yourselves whether you have verily seen at all, or trusted at all, 'the Light of life.'