But it is apparent from our Lord's description of the subject-matter of the Spirit's witness that here He has especially in view the function of the Spirit as an inward teacher and strengthener of the moral powers. He is the fellow-witness of the Apostles, mainly and permanently, by enlightening men in the significance of the facts reported by them, and by opening the heart and conscience to their influence.
The subject-matter of the Spirit's testimony is threefold: "He will convict the world in respect of sin, and of righteousness, and of judgment."
I. He should convict the world of sin. No conviction cuts so deeply and produces results of such magnitude as the conviction of sin. It is like subsoil ploughing: it turns up soil that nothing else has got down to. It alters entirely a man's attitude towards life. He cannot know himself a sinner and be satisfied with that condition. This awakening is like the waking of one who has been buried in a trance, who wakes to find himself bound round with grave-clothes, hemmed in with all the insignia of corruption, terror and revulsion distracting and overwhelming his soul. In spirit he has been far away, weaving perhaps a paradise out of his fancies, peopling it with choice and happy society, and living through scenes of gorgeous beauty and comfort in fulness of interest and life and felicity; but suddenly comes the waking, a few brief moments of painful struggle and the dream gives place to the reality, and then comes the certain accumulation of misery till the spirit breaks beneath its fear. So does the strongest heart groan and break when it wakes to the full reality of sin, when the Spirit of Christ takes the veil from a man's eyes and gives him to see what this world is and what he has been in it, when the shadows that have occupied him flee away and the naked inevitable reality confronts him.
Nothing is more overwhelming than this conviction, but nothing is more hopeful. Given a man who is alive to the evil of sin and who begins to understand his errors, and you know some good will come of that. Given a man who sees the importance of being in accord with perfect goodness and who feels the degradation of sin, and you have the germ of all good in that man. But how were the Apostles to produce this? how were they to dispel those mists which blurred the clear outline of good and evil, to bring to the self-righteous Pharisee and the indifferent and worldly Sadducee a sense of their own sin? What instrument is there which can introduce to every human heart, howsoever armoured and fenced round, this healthy revolution? Looking at men as they actually are, and considering how many forces are banded together to exclude the knowledge of sin, how worldly interest demands that no brand shall be affixed to this and that action, how the customs we are brought up in require us to take a lenient view of this and that immorality, how we deceive ourselves by sacrificing sins we do not care for in order to retain sins that are in our blood, how the resistance of certain sins makes us a prey to self-righteousness and delusion--considering what we have learnt of the placidity with which men content themselves with a life they know is not the highest, does there seem to be any instrument by which a true and humbling sense of sin can be introduced to the mind?
Christ, knowing that men were about to put Him to death because He had tried to convict them of sin, confidently predicts that His servants would by His Spirit's aid convince the world of sin and of this in particular--that they had not believed in Him. That very death which chiefly exhibits human sin has, in fact, become the chief instrument in making men understand and hate sin. There is no consideration from which the deceitfulness of sin will not escape, nor any fear which the recklessness of sin will not brave, nor any authority which self-will cannot override but only this: Christ has died for me, to save me from my sin, and I am sinning still, not regarding His blood, not meeting His purpose. It was when the greatness and the goodness of Christ were together let in to Peter's mind that he fell on his face before Him, saying, "Depart from me, O Lord, for I am a sinful man." And the experience of thousands is recorded in that more recent confession: