It was a Tuesday, 177 years ago, on October 22, 1844 when many believers  left everything and waited for Jesus’ coming. They waited and waited and waited, but nothing happened. The day passed as any other ordinary day and night came. Then the sunrise of the next day came. And then the utter disappointment came. This is why that day and event is referred as the “Great Disappointment”. As the Millerite Henry Emmons wrote:
“I waited all Tuesday [October 22] and dear Jesus did not come; – I waited all the forenoon of Wednesday, and was well in body as I ever was, but after 12 o'clock I began to feel faint, and before dark I needed someone to help me up to my chamber, as my natural strength was leaving me very fast, and I lay prostrate for 2 days without any pain– sick with disappointment.” 
What went wrong? Why did Jesus not come as many had predicted and believed? Was there a mistake in their belief? To understand this event and what led to the disappointment of many, we have to go back when it all started.
How It Started
In 1818, William Miller, while studying the prophetic book of Daniel in the Bible, arrived at the conclusion that Jesus would soon return to earth. He came to this understanding by interpreting the prophetic period of 2300 days in Daniel 8:14 where it says: “And he said to me, ‘For two thousand three hundred days; then the sanctuary shall be cleansed.’” Miller understood incorrectly that the sanctuary in Daniel 8:14 was our earth, and its cleansing the end of this world when fire will consume everything, according to 2 Peter 3:7. He took the date of 457 B.C. as the beginning of the 2300 prophetic period. This is the date when Artaxerxes, the king of Persia, commanded “to restore and build Jerusalem” (Daniel 9:25). Using the day-year principle from Numbers 14:34 and Ezekiel 4:6, and with the 457 B.C. as the start date, he concluded that the end date for 2300 days would fall on 1843, when the sanctuary must be cleansed. In his study, Miller understood that the exact beginning of the 2300 prophetic period started on March 21, 457 and thus the 2300th year would fall in the spring of March 21, 1842 to March 21, 1844.
William Miller felt the urge to tell everyone the news that the end of this world will be soon coming, but for thirteen years he procrastinated because he thought that he might be in error and did not want to mislead others. Finally, the burden of the message seemed too much to bear by keeping it to himself. He felt the call to preach, but asked God for a clear sign through an invitation to preach. By this time, he was a farmer in his fifties and felt it was highly unlikely that such an invitation would come unless directly orchestrated by God Himself. Within thirty minutes, he heard knocking at the door from his nephew bringing the invitation to preach about the second advent of Jesus because of a cancellation of the minister who was supposed to speak. It was the sign. 
As he began to preach, many people accepted the message of the soon coming of Jesus. This became to be known as the Advent movement. Describing the Advent movement ignited by William Miller’s preaching, Ellen G. White stated:
“In nearly every town there were scores, in some, hundreds, converted as a result of his [William Miller] preaching. In many places Protestant churches of nearly all denominations were thrown open to him, and the invitations to labor usually came from the ministers of the several congregations. It was his invariable rule not to labor in any place to which he had not been invited, yet he soon found himself unable to comply with half the requests that poured in upon him. Many who did not accept his views as to the exact time of the second advent were convinced of the certainty and nearness of Christ's coming and their need of preparation. In some of the large cities his work produced a marked impression. Liquor dealers abandoned the traffic and turned their shops into meeting rooms; gambling dens were broken up; infidels, deists, Universalists, and even the most abandoned profligates were reformed, some of whom had not entered a house of worship for years. Prayer meetings were established by the various denominations, in different quarters, at almost every hour, businessmen assembling at midday for prayer and praise. There was no extravagant excitement, but an almost universal solemnity on the minds of the people. His work, like that of the early Reformers, tended rather to convince the understanding and arouse the conscience than merely to excite the emotions.” 
As the time passed and and nothing happened from 21 March, 1843 to 21 March, 1844, which was the last year of the 2300 year prophecy, many Advent believers suffered disappointment, which is often called and referred as the “first disappointment.” Miller and the Advent believers using Bible texts as Habakkuk 2:3 and the parable of the ten virgins from Matthew 25:5-6, understood there is a tarrying time for the coming of Lord Jesus. Later in the summer of 1844, Samuel Sheffield Snow, using the Karaite Jewish calendar, pointed to the coming of the Lord as happening in the “seventh month”, on the Day of Atonement, which fall on October 22, 1844.  The date in the Rabbinical Jewish calendar for the Day of Atonement for the year of 1844 was September 23. The Advent believers chose the Karaite Jewish calendar because it was favouring a more literal approach to the Bible.  So, thus the new date gave hope and courage to the Advent believers for the soon coming of Jesus.
The Progression of the Advent Movement
The Advent movement swept across North America and lasted for about 10 years until the day that Christ was believed to make His appearance in 1844. Many people believed the Advent message and made drastic preparations for it in the form of personal soul-searching, ministry to others, and management (or lack thereof) of personal goods. They sold their homes and properties and gave the money to the poor or for the spreading of the Advent message. Many left their fields unharvested in 1844 for why was the harvest needed when they wouldn’t live through another winter on Earth and would be rejoicing in heaven? Earth was to be cleansed by fire anyways. They all waited for the soon coming of Jesus. The date came and passed and nothing happened. The Advent believers were disappointed and many were crying in utter despair. Many left and took the ranks of the scoffers. But those who searched for the Lord with all their hearts chose to pray and remained faithful to Him, despite the disappointment that they just faced. And God remained with them through their pain.
The Correct Interpretation and Lessons from the Great Disappointment
The path of faith is not a smooth one and free of disappointments. God allowed His people to go through this experience to make them stronger and test the faith of each one. The Great Disappointment proved to be too much to bear for some people who ended up abandoning their faith. A small portion of the great Advent movement choose to remain faithful, and, through further prayer and study, see if they had erred anywhere in their interpretation of the prophecy. Even though this experience was very disappointing, Ellen G. White refers to 1844 as “the happiest year”  of her life.
Even though it was a bitter experience, the true believers prayed more earnestly to see where they were wrong. One such believer was Hiram Edson, who had a revelation from God while walking in a cornfield and was directed to read the book of Hebrews carefully. Upon examining the book of Hebrews, particularly the 8th and 9th chapters, he came to believe that their error was in their understanding of the event that was supposed to take place on October 22, 1844. Instead of interpreting the sanctuary from Daniel 8:14 to be our earth, they came to the realization that, according to Hebrews 8 and 9, the sanctuary in Daniel 8:14 refers to one in heaven and “it was therefore necessary that the patterns of things in the heavens should be purified…” (Hebrews 9:23), and where Jesus “as a minister of the sanctuary” (Hebrews 8:2) entered from the Holy to the Holy of Holies (Hebrews 9:23-27; Hebrews 10:19) So, thus they understood that October 22, 1844 marked the beginning of Christ’s ministry in the Most Holy compartment in the heavenly sanctuary. About this discovery, Ellen G. White wrote:
“The subject of the sanctuary was the key which unlocked the mystery of the disappointment of 1844. It opened to view a complete system of truth, connected and harmonious, showing that God's hand had directed the great advent movement and revealing present duty as it brought to light the position and work of His people.” 
“The question, What is the sanctuary? is clearly answered in the Scriptures. The term ‘sanctuary,’ as used in the Bible, refers, first, to the tabernacle built by Moses, as a pattern of heavenly things; and, secondly, to the ‘true tabernacle’ in heaven, to which the earthly sanctuary pointed. At the death of Christ the typical service ended. The ‘true tabernacle’ in heaven is the sanctuary of the new covenant. And as the prophecy of Daniel 8:14 is fulfilled in this dispensation, the sanctuary to which it refers must be the sanctuary of the new covenant. At the termination of the 2300 days, in 1844, there had been no sanctuary on earth for many centuries. Thus the prophecy, ‘Unto two thousand and three hundred days; then shall the sanctuary be cleansed,’ unquestionably points to the sanctuary in heaven.” 
Two months later, in December of 1844, Ellen G. White had the well-known vision of the narrow path where she saw God leading a small group of people on the narrow path. This was an encouragement for the ones who had remained faithful and a sign that God is leading His people towards the New Jerusalem.
The Great Disappointment was allowed to test the authenticity of people’s faith. Would they continue to pray and study the Scriptures with the same fervent spirit as they did before it? Or did they merely act out of fear or excitement? As Ellen G. White describes:
“The disappointment also, though the result of their own misapprehension of the message which they gave, was to be overruled for good. It would test the hearts of those who had professed to receive the warning. In the face of their disappointment would they rashly give up their experience and cast away their confidence in God's word? or would they, in prayer and humility, seek to discern where they had failed to comprehend the significance of the prophecy? How many had moved from fear, or from impulse and excitement? How many were halfhearted and unbelieving? Multitudes professed to love the appearing of the Lord. When called to endure the scoffs and reproach of the world, and the test of delay and disappointment, would they renounce the faith? Because they did not immediately understand the dealings of God with them, would they cast aside truths sustained by the clearest testimony of His word?
“This test would reveal the strength of those who with real faith had obeyed what they believed to be the teaching of the word and the Spirit of God. It would teach them, as only such an experience could, the danger of accepting the theories and interpretations of men, instead of making the Bible its own interpreter. To the children of faith the perplexity and sorrow resulting from their error would work the needed correction. They would be led to a closer study of the prophetic word. They would be taught to examine more carefully the foundation of their faith, and to reject everything, however widely accepted by the Christian world, that was not founded upon the Scriptures of truth.” 
Those who chose to remained faithful were scoffed and deride. One of them was William Miller himself, the one who started the Advent movement. How did he feel? What did he think? Well, these were his words, spoken just a few weeks after the Great Disappointment:
“Although surrounded by enemies and scoffers, my mind is perfectly calm and my hope in the coming Christ is as sure as ever… I have fixed in my mind upon another time and here I mean to stand until God gives me more light. And that is Today, Today Today. Until He comes and I see Him, my soul yearns for him.” 
What faith! An unwavering faith that Jesus will come and an earnest desire to follow and see Him. Does your soul yearn to see Jesus? He will come soon.
“For yet a little while, And He who is coming will come and will not tarry.”
- Hebrews 10:37
 George R. Knight, Millennial Fever and the End of the World (Boise, Idaho: Pacific Press, 1993), p. 217-218.
 C. Mervyn Maxwell, Tell It To The World (Pacific Press Publishing Association, Idaho, 1976) p. 13-14.
 Ellen G. White, The Great Controversy, p. 331.
 C. Mervyn Maxwell, Tell It To The World (Pacific Press Publishing Association, Idaho, 1976) p. 26-27.
 P. Gerard Damsteegt, Early Adventist Timesettings and Their Implications for Today, Journal of the Adventist Theological Society, April 1, 1993.
 Ellen G. White, Testimonies for the Church, vol. 1, p. 54.
 Ellen G. White, The Great Controversy, p. 423.
 The Great Controversy, p. 417.
 The Great Controversy, p. 353-354.
 The Midnight Cry, Dec. 5, 1844, pp. 179, 180.