The natural history of a parable is like the (probable) natural history of a pearl. Something alien and irritating has alighted upon life, and forthwith a covering of pure and precious matter is thrown over it. After this manner, indeed, as we have already noted, a greater than the parable came. In this way redemption began, and grew. Sin entered Eden and fastened upon that image of God which had appeared on earth in the person of primeval man; forthwith holy promises from heaven began to cluster round the sin-spot. As age succeeded age these promises distilled like dew and crystallized around the original nucleus, until redemption was completed in the sacrifice of Christ and the ministry of the Spirit: that glorious gospel on which we now fondly look, gathered round the fall. The sin of man, though not the cause of God's salvation, became its occasion and determined its form. The particular lessons which Jesus taught in the course of his ministry, followed in this respect the analogy of his redeeming work as a whole; in most cases his instructions were called forth and fashioned by hard, bold outstanding sins. Some of the brightest jewels which shine in the life of Christ are the pure pearly coverings which he threw around Pharisaic pride, or Sadducean unbelief, or the self-righteous stumbles of his own disciples. Thus he made the wrath, and the malice, and the deceit of men to show forth his own praise; thus rust-spots were converted into shining pearls; thus human errors, as they sprung up, were seized and choked and buried under a mantle of glorious grace.