The truth is, there is no ready-made theory here for any of us. All our attainments in it are tentative and provisional; which does not hinder, however, that they may be very real. When we believe in Christ we become aware that there is a lesson in this department to be learned, and we become willing, in a measure, to learn it. But we should learn little were it not for three great teachers that take us in hand.
The first is the inevitable conflict with sin and temptation. The Christian must, at all events, strive against known sin, and he must hold himself ready to resist the onset of temptation, watching and praying. In this discipline he soon learns how sin is entangled for him with much that in other respects seems desirable or good; he learns that in rejecting sin he must forgo some things which on other accounts he gladly would embrace. It is often a painful conflict through which he has to pass. Now in seeking help from his Lord, and entering into the fellowship of the mind of Christ, he is not only strengthened to repel the sin, but also learns to submit willingly to any impoverishment or abridgement of earthly life which the conflict entails. He is taught in practice, now in one form, now in another, to count _all_ things but loss--to lower the overweening estimate of earthly treasure and let it go, dying to it with his dying Lord.
Then, besides, there is the discipline of suffering. Sorrow, indeed, is not peculiar to Christians. Of it, all are partakers. But Christian endurance is part of a fellowship with Christ, in which we learn of Him. In the warm air of prosperity a hot mist rises round the soul, that hides from view the great realities, and that deceives and misleads us with its vain mirage. But in suffering, taken in Christ's way and in fellowship with Him, in the pain of disappointment and of loss, and especially in the exercise of submission, we are taught feelingly where our true treasure is; and we are trained to consent to separations and privations, for the sake of Christ, and under the influence of the love of Christ.
And, lastly, the growth of Christian experience and Christian character deepens our impressions of the worth of Christ's salvation, and gives more body and more ardour to Christian hope. As that world with its perfect good draws the believer, as it becomes more visible to faith and more attractive, his grasp of this world becomes, perhaps, not less kindly, but it becomes less tenacious. Knowledge, such as the schools of earth afford, we still feel to be desirable and good. Love, under the conditions which earth supplies for its exercise, we still feel to be very dear. The activities which call out courage and resource, we still feel to be interesting and worthy. Yet knowledge proves to be but in part. And love, if it does not die, needs for its health and security a purer air. And in the problems of active life failure still mingles with success. But the love of God which is in Jesus Christ grows in worth and power; so that, in new applications of the principle, we learn afresh to "count all things but loss for the excellency of the knowledge of Christ."
In a word, then, that we may grow into the mind of Christ, sufferings and self-denials are appointed to come into experience. He sets them for us; we should not wisely set them for ourselves. They come in the conflict with sin or in the ordinary discipline of life. Either way they become for believers the fellowship of Christ's sufferings; for they are taken in Christ's way, under His eye, endured in the strength of His truth and grace and salvation. So believers become more conformable to His death. Hence this discipline of trial is indispensable to all disciples.