_Acts_ xvi. 26. When _Paul_ and _Silas_ were in prison. _At mid-night when they pray'd, and sang hymns to God, suddenly there was a great earthquake; so that the foundations of the prison were shaken. And immediately all the doors were opened, and every one's bands were loosed._ Observe the consequence it had upon the gaoler; _He called for a light, and sprang in, and came trembling, and fell down before Paul and Silas, and said, Sirs, what must I do to be saved?_ The gaol trembled; and the gaoler trembled, as is observed by a writer on this head, an earthquake could _soften_ his _hard_ heart, and _open_ what he had _lock'd_. It awaken'd him out of his spiritual slumber, as well as his natural sleep, and made his conscience, as well as the foundations of the prison, to quake. A bad conscience is _as a troubled sea, that cannot rest, but casteth up mire, and clay_. The gaoler perceiv'd the celestial warning, and made a proper use of it. There are many circumstances in the nature of earthquakes, which render them peculiarly proper to be the instruments in God's hand, to give warning to a people, to amend their ways. The _suddenness_ is one. We saw, not long ago, what an effect was produced by a solar eclipse, tho' it was expected long before. We had the prediction, and calculations about it in all our almanacs; yet there was an universal seriousness that followed it. All that morning, we could walk the street, without hearing an oath, and the churches were full, in time of prayer. But the _suddenness_ of an earthquake that comes at an instant, unthought of, without warning, that seems to bring unavoidable death along with it; is able to touch an adamantin heart. To see death stalking o'er a great city, ready to sweep us all away, in an instantaneous ruin, without a single moment to recollect our thoughts; this is fear without remedy; this is far beyond battle and pestilence. The lightning and thunderbolt, _the arrow that flieth by day_, may suddenly take off an object or two, and leave no space for repentance: but what horror can equal that, when above a million of people are liable to be buried, in one common grave! Another consideration that inhances the dread of earthquakes, is the _unavoidableness_ of the calamity. Famine, and war, and rebellion, and pestilence we may run from, the disease among the cattle, and locusts, and the like stripes of angry heaven, we may have some chance to escape: but no means, no precaution, no remedy, no prudence can screen us, from so universal a desolation as this: 'tis as the presence of God. Whither then can we go to hide ourselves? Must we call upon the rocks and mountains, to cover, and shelter us from the divine wrath! _And they shall go into the holes of the rocks, and into the caves of the earth, for fear of the_ Lord, _and for the glory of his majesty; when he ariseth to shake terribly the earth_. Alas, those are the very instruments he employs for our destruction; to be our tombstones!