Gleaning a few choice excerpts from "George Whitefield's Journals," one of my favorite books (boldface & italics mine). These are all taken from the year 1739...

Monday, March 19.  After having refreshed myself and friends by reading a packet of letters from London, and dispatched some other business, according to appointment, I set out for Bath, and got thither about three in the afternoon.  Dinner being ended, through great weakness of body, and sickness in my stomach, I was obliged to lie down upon the bed; but the hour being come for my preaching, I went, weak and languid as I was, depending on the Divine Strength, and, I think, scarce ever preached with greater power.  There were about four or five thousand of high and low, rich and poor, to hear.  As I went along, I observed many scoffers, and when I got upon the table to preach, many laughed; but before I had finished my prayer, all was hushed and silent, and ere I had concluded my discourse, God, by His Word, seemed to impress a great awe upon their minds; for all were deeply attentive, and seemed much affected with what had been spoken.  Men may scoff for a little while, but there is something in this foolishness of preaching which will make the most stubborn heart to bend or break.  "Is not My Word like fire," saith the Lord, "and like a hammer that breaketh the rock in pieces?"

Friday, May 12 ... Many came to me this morning, acquainting me what God had done in their souls by my preaching in the fields.  In the evening, I preached to about twenty thousand people at Kennington as usual, the weather continuing remarkably fair whilst I was delivering my Master's message.  I offered Jesus Christ to all who could apply Him to their hearts by faith.  Oh that all would embrace Him!  The Lord make them willing in the day of His power.

Sunday, May 13. Preached this morning to a prodigious number of people in Moorfields, and collected for the orphans £52 19s. 6d., above £20 of which was in halfpence.  Indeed, they almost wearied me in receiving their mites, and they were more than one man could carry home.  Went to public worship twice and preached in the evening to near sixty thousand people.  Many went away because they would not hear; but God enabled me to speak so that the best part of them could understand me well, and it is very remarkable what a deep silence is preserved whilst I am speaking.  After sermon, I made another collection of £29 17x. 8d, and came home deeply humbled with a sense of what God has done for my soul. I doubt not but that many self-righteous bigots, when they see me spreading out my hands to offer Jesus Christ freely to all, are ready to cry out, "How glorious did the Rev. Mr. Whitefield look to-day, when, neglecting the dignity of a clergyman, he stood venting his enthusiastic ravings in a gown and cassock upon a common, and collecting mites from the poor people." But if this is to be vile, Lord grant that I may be more vile.  I know this foolishness of preaching is made instrumental to the conversion and edification of numbers.  Ye Pharisees mock on, I rejoice, yea, and will rejoice.

Friday, May 18. ... As the walls of Jericho once fell down at the sound of a few rams' horns; so I hope even this foolishness of preaching, under God, will be a means of pulling down the Devil's strongholds, which are in and about the City of London...

Thursday, June 7.  Received two letters from persons, confessing that they came to hear me out of a bad motive, but were apprehended by the free grace of Jesus Christ...

Wednesday, July 18. ... I reached Abingdon, twenty-two miles from Cirencester, about seven, and preached to several thousands soon after I came in.  Much opposition had been made against my coming.  The landlord, whose house we offered to put up at, genteellly told us he had not room for us; and numberless prejudices had been industriously spread to prevent my success.  But God's Word will make its own way, let men say what they please.  Our weapons are not carnal, but mighty through the Divine Power, to the pulling down of Satan's strongholds.

Thursday, July 19.  At the request of several well-disposed people, preached again this morning, though not to so great a number as before.  A sweet power was felt amongst us.  The hearers melted into tears under the Word.  Oh, what a sudden alteration does this foolishness of preaching make in the most obstinate hearts.  'Tis but for God to speak the word, and the lion is turned into a lamb.  Oh, that we were like that dear Lamb of God, Who died to take away the sins of the world.

Saturday, July 28.  ... Preached at Blackheath in the evening and came home rejoicing.  The bills which are sent to me, plainly prove that God has worked on numbers of souls. At the judgment day, we shall see what good has been done by this foolishness of preaching.  Many, I believe, come to the fields to worship the Father in spirit and in truth.  God seeketh such to worship Him.

Do we really believe God's Word is a hammer and a fire? Do we believe God's Holy Spirit delights to work through preaching and prayer to save souls just He did in the days of George Whitefield? How often are we as 21st century Christians tempted to think we have evolved in some way from the 18th century days of Whitefield, or from the 1st century days of the early Church, so that when we look up and see those high and thick Jericho walls –– those stony, hard hearts of unbelievers, skeptics, mockers, and doubters –– rather than standing firm in faith, we begin to slip and slide into compromising –– and soon enough we have cast aside God's appointed means to convict and arrest and save souls and magnify His glory:  this foolishness of preaching? When faced with intimidating and daunting Jericho walls, how often do we find ourselves relying on worldly wisdom, carnal weapons, earthly power, human ingenuity, and fleshly manipulation –– rather than standing fast on God's Word, trusting in God's might, relying on God's wisdom and power, and preaching Christ and Him crucified? Are we all too ready to jettison God's instrumental means out of fear of looking vile, undignified, foolish, and weak in the eyes of men?

I Corinthians 1:18  For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God. 19  For it is written, I will destroy the wisdom of the wise, and will bring to nothing the understanding of the prudent. 20  Where is the wise? where is the scribe? where is the disputer of this world? hath not God made foolish the wisdom of this world? 21  For after that in the wisdom of God the world by wisdom knew not God, it pleased God by the foolishness of preaching to save them that believe. 22  For the Jews require a sign, and the Greeks seek after wisdom: 23  But we preach Christ crucified, unto the Jews a stumblingblock, and unto the Greeks foolishness; 24  But unto them which are called, both Jews and Greeks, Christ the power of God, and the wisdom of God. 25  Because the foolishness of God is wiser than men; and the weakness of God is stronger than men.

II Chronicles 16:7  And at that time Hanani the seer came to Asa king of Judah, and said unto him, Because thou hast relied on the king of Syria, and NOT relied on the LORD thy God, therefore is the host of the king of Syria escaped out of thine hand. 8  Were not the Ethiopians and the Lubims a huge host, with very many chariots and horsemen? yet, because thou didst rely on the LORD, he delivered them into thine hand. 9  For the eyes of the LORD run to and fro throughout the whole earth, to shew himself strong in the behalf of them whose heart is perfect toward him. Herein thou hast done foolishly: therefore from henceforth thou shalt have wars. 10  Then Asa was wroth with the seer, and put him in a prison house; for he was in a rage with him because of this thing. And Asa oppressed some of the people the same time.

Revelation 6:12  When he opened the sixth seal, I looked, and behold, there was a great earthquake, and the sun became black as sackcloth, the full moon became like blood, 13  and the stars of the sky fell to the earth as the fig tree sheds its winter fruit when shaken by a gale. 14  The sky vanished like a scroll that is being rolled up, and every mountain and island was removed from its place. 15  Then the kings of the earth and the great ones and the generals and the rich and the powerful, and everyone, slave and free, hid themselves in the caves and among the rocks of the mountains, 16  calling to the mountains and rocks, “Fall on us and hide us from the face of him who is seated on the throne, and from the wrath of the Lamb, 17  for the great day of their wrath has come, and who can stand?”

“Behold, the Lamb of God, who takes away the sin of the world!"

John 3:36  Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him.

Romans 3:21  But now the righteousness of God has been manifested apart from the law, although the Law and the Prophets bear witness to it— 22  the righteousness of God through faith in Jesus Christ for all who believe. For there is no distinction: 23  for all have sinned and fall short of the glory of God, 24  and are justified by his grace as a gift, through the redemption that is in Christ Jesus, 25  whom God put forward as a propitiation by his blood, to be received by faith. This was to show God's righteousness, because in his divine forbearance he had passed over former sins. 26  It was to show his righteousness at the present time, so that he might be just and the justifier of the one who has faith in Jesus.

Right now God is commanding you to repent and believe, so you might be saved from His just wrath by grace through faith in the blood of His Son, Jesus Christ. One day the Lord Jesus Christ will return to judge the living and the dead, and if you have not believed in Him, you will not be hidden from His wrath –– His wrath will remain on you –– and you will not be able to stand before Him, and you will be cast off into eternal punishment and everlasting fire.

Acts 17:29  Being then God's offspring, we ought not to think that the divine being is like gold or silver or stone, an image formed by the art and imagination of man. 30  The times of ignorance God overlooked, but now he commands all people everywhere to repent, 31  because he has fixed a day on which he will judge the world in righteousness by a man whom he has appointed; and of this he has given assurance to all by raising him from the dead.”

32  Now when they heard of the resurrection of the dead, some mocked. But others said, “We will hear you again about this.” 33  So Paul went out from their midst. 34  But some men joined him and believed, among whom also were Dionysius the Areopagite and a woman named Damaris and others with them.