A startling providential dispensation was one of the means by which the spiritual nature of this jailer was roused. Only one, effectual so far as it went, but not complete in itself. It was preparatory and auxiliary to the action of the Holy Spirit, the instrument by which the Spirit did His special work of convincing the man of sin. Thus it is that outward events and circumstances are made to co-operate with God in the conversion of a soul. The way in which the Spirit works is a mystery, akin to that in which one human mind acts upon another. But the _means_ of this spiritual action is no mystery. We use speech, external appliances of various kinds; the Divine Spirit does the same. In the case of the jailer he employed the earthquake together with the calm faith, the perfect serenity, of the apostles at a moment which was to himself a moment of terror, and which would also have been a moment of terror to them had they not been the Christians they were. A great joy; a great sorrow, commotion, loss, alarm, the apparent nearness of death; daily mercies, the "means of grace," the Word of God, the ministry of the gospel--through all these the Spirit works. They are powerless in themselves; they can only become mighty as used by Him. It is obvious at a glance that this man's spiritual nature _was_ roused. Spiritual realities burst in upon his mind in all their awful momentousness. His whole soul was suddenly concentrated in a sense of his ruin. Hence the short, sharp question--the question which sprung from an inward agony--"What must I do to be saved?" That question must be answered, if it can be--answered on the instant! There is a tremendous depth of meaning in it. It is as though a lightning flash had in a moment illuminated the man's whole spiritual condition, bringing out every feature of it into startling distinctness. All the fears and the aspirations of his immortal being are here; his past life with all its sin, his remorse, his dread of judgment, his terror in the presence of God--all are here; he feels himself to be a lost man. How can he be saved? In his question there is no hint of self-righteousness or of self-confidence, or even of the remotest hope in himself. He does not ask, like "the young man in the gospel," "What good thing must I do that I may inherit eternal life?" The question of the young man is leisurely; the question of the jailer is hurried, under the feeling that there is not a moment to be lost. Helpless and hopeless, he wants but one thing, and that is to be "saved." Of course his "What must I do?" indicates that he is willing and ready to comply with any possible terms; yet it is not a question of conscious strength--it is rather the question of despair.