What kind of "stuff" does God use for his extraordinary work?

I relished this bit from Charles Spurgeon's revival sermon, "The Story of God's Mighty Acts":

A friend who called to see me yesterday, tells me that the lowest and vilest men, the most depraved females in Belfast, have been visited with this extraordinary epilepsy, as the world calls it; but with this strange rushing of the spirit, as we have it. Men who have been drunkards have suddenly felt an impulse compelling them to pray. They have resisted; they have sought to their cups in order to put it out; but when they have been swearing, seeking to quench the Spirit by their blasphemy, God has at last brought them on their knees, and they have been compelled to cry for mercy with piercing shrieks, and to agonize in prayer; and then after a time, the Evil one seems to have been cast out of them, and in a quiet, holy, happy frame of mind, they have made a profession of their faith in Christ, and have walked in his fear and love. Roman Catholics have been converted. I thought that an extraordinary thing; but they have been converted very frequently indeed in Ballymena and in Belfast. In fact, I am told the priests are now selling small bottles of holy water for people to take, in order that they may be preserved from this desperate contagion of the Holy Spirit. This holy water is said to have such efficacy, that those who do not attend any of the meetings are not likely to be meddled with by the Holy Spirit—so the priests tell them. But if they go to the meetings, even this holy water cannot preserve them—they are as liable to fall prey to the Divine influence. I think they are just as likely to do so without as with it.

All this has been brought about suddenly, and although we may expect to find some portion of natural excitement, yet I am persuaded it is in the main a real, spiritual, and abiding work. There is a little froth on the surface, but there is a deep running current that is not to be resisted, sweeping underneath, and carrying everything before it. At least there is something to awaken our interest, when we understand that in the small town of Ballymena on market day, the publicans have always taken one hundred pounds for whiskey, and now they cannot take a sovereign all day long in all the public houses. Men who were once drunkards now meet for prayer, and people after hearing one sermon will not go until the minister has preached another, and sometimes a third; and at last he is obliged to say: "You must go, I am exhausted." Then they will break up into groups in their streets and in their houses, crying out to God to let this mighty work spread, that sinners may be converted unto him. "Well," says one, "we cannot believe it." Very likely you cannot, but some of us can, for we have heard it with our ears, and our fathers have told us the mighty works that God did in their days, and we are prepared to believe that God can do the same works now.

I must here remark again, in all these old stories there is one very plain feature. Whenever God has done a mighty work it has been by some very insignificant instrument. When he slew Goliath it was by little David, who was but a ruddy youth. Lay not up the sword of Goliath—I always thought that a mistake of David—lay up, not Goliath's sword, but lay up the stone, and treasure up the sling in God's armory for ever. When God would slay Sisera, it was a woman that must do it with a hammer and a nail. God has done his mightiest works by the meanest instruments: that is a fact most true of all God's works—Peter the fisherman at Pentecost, Luther the humble monk at the Reformation, Whitefield the potboy of the Old Bell Inn at Gloucester in the time of the last century's revival; and so it must be to the end. God works not by Pharaoh's horses or chariot, but he works by Moses' rod; he doth not his wonders with the whirlwind and the storm; he doth them by the still small voice, that the glory may be his and the honour all his own.

Doth not this open a field of encouragement to you and to me?

Yes sir, it does.