Problems with the Second Coming
Numerous passages in the Bible portray Jesus clearly stating that the Second Coming would occur within the lifetime of his disciples.
"Verily I say unto you, This generation shall not pass, till all these things be fulfilled."
"This generation" refers to a span of 30-40 years, thus placing the date of the second coming before the deaths of the disciples. C.S. Lewis called this "the most embarrassing verse in the Bible" in The World’s Last Night and Other Essays.
Three more verses explicitly state that some of the people listening to Jesus as he preached would not die before he returned.
"Verily I say unto you, There be some standing here, which shall not taste of death, till they see the Son of man coming in his kingdom."
"And he said unto them, Verily I say unto you, That there be some of them that stand here, which shall not taste of death, till they have seen the kingdom of God come with power."
- — Mark 9:1
"But I tell you of a truth, there be some standing here, which shall not taste of death, till they see the kingdom of God."
Jesus also told people that "the time is short and they should not get married, not mourn, not be happy, not buy things, and not live "in the world". This again indicates that Jesus himself believed his return to be extremely imminent.
"What I mean, brothers, is that the time is short. From now on those who have wives should live as if they had none; those who mourn, as if they did not; those who are happy, as if they were not; those who buy something, as if it were not theirs to keep; those who use the things of the world, as if not engrossed in them. For this world in its present form is passing away.""
"But the end of all things is at hand: be ye therefore sober, and watch unto prayer."
The term "Second Coming" never appears in the New Testament. Furthermore, in none of the Epistles which were written prior to the Gospels is Jesus ever referred to as "coming again" or "coming back" or "returning." The only terms used are "coming" or "will come." If the Jesus of the Gospels is legendary fiction, then this is exactly what would be expected if early Christians were looking forward to the First Coming of Jesus, much as practitioners of Judaism are still looking forward to the First Coming of the Messiah, not the Second Coming.
Christian beliefs about the Second Coming
Obviously Jesus did not return within the lifetime of his disciples. Many Christians today still believe that the Second Coming is imminent, and talk about the impending rapture. As we can see elsewhere in the Bible, this is nothing new. Later in the story, the disciples begin complaining to Peter. As a result, Peter invents an ad hoc answer.
"Knowing this first, that there shall come in the last days scoffers, walking after their own lusts, and saying, Where is the promise of his coming? For since the fathers fell asleep, all things continue as they were from the beginning of the creation.... But, beloved, be not ignorant of this one thing, that one day is with the Lord as a thousand years, and a thousand years as one day."
Thus an ad hoc case is made that when Jesus said that his return was "imminent" and "at hand" he really meant "thousands of years from now".