Judgment must begin at the house of God
1 Peter 4:17
17For the time [is come] that judgment must begin at the house of God: and if [it] first [begin] at us, what shall the end [be] of them that obey not the gospel of God?
Any verse of the bible can be taken out of context or otherwise twisted to "prove" just about anything. On the surface, this particular verse would immediately seem to support Camping's last days outline. In fact, I would venture to say that this is possibly the clearest and most definitive supporting verse for an abandonment of the church. But, to someone not familiar with Camping's "Depart Out" theology, would that same person conclude the same as Camping? Not likely. Let's examine the verse, it's audience, and the surrounding context more closely.
Context
When Peter wrote those words, who was he talking to? Answer: The church. To be more specific, the elect "strangers scattered throughout Pontus, Galatia, Cappadocia, Asia, and Bithynia" (see address in 1:1-2, also see the personal greetings at the end of the book.). That is, Peter is particularly writing to Christians who existed at the time Peter wrote the letter, people who walked around on the earth during the time of Peter's ministry, including people who had met him and listened to him in person. Not a single person living today can make that claim. When Peter said judgement must begin with "us"(v.17), he must have been talking to those people who were living at that time, including himself (he said "us" not "them", or "you"). That means what he was talking about also took place around that time in history.
Peter anticipated that those he was writing to would have to endure much trouble: He writes "now for a season, if need be, ye are in heaviness through manifold temptations:" (1:6). Why? So "That the trial of your faith, being much more precious than of gold that perisheth, though it be tried with fire, might be found unto praise and honour and glory..." (1:7)
The "now", "us", "at hand" time indicators continue into chapter 4:
1 Peter 4:7
7the end of all things is at hand: be ye therefore sober, and watch unto prayer.
1 Peter 4:12
12think it not strange concerning the fiery trial which is to try you,
Since verse 17 also referrs to the same "us", it would fit that that Peter's warnings are referring to the impending destruction of Jerusalem in AD 70. God pronounced Judgement on His people, Isreal (see Daniel, for instance), and it was carried out exactly as prophesied. As Jesus said in Matthew 23:38, "behold, you house is left unto you desolate". Notice that Jesus said "is" not "will be." He spoke in the present-tense, not prophetic future-tense.
Judgement
Though the word "judgment" is commonly used in a way that is negative, that is not always the case. Think of the way that a judge in court judges a case to determine if a person is guilty. The judgement itself is not the punishment. The judgement is the process by which a person is determined to be guilty or not guilty. In the case of 1 Peter 4:17, God is "judging" His people to purge the saved from the unsaved, the way a refiner melts gold to burn away and seperate impurities from the gold. This explanation is in agreement with what Peter writes earlier in the book:
1 Peter 1:7
7That the trial of your faith, being much more precious than of gold that perisheth, though it be tried with fire, might be found unto praise and honour and glory...
Conclusion
The book of 1 Peter seems to be almost, if not exclusively, speaking of Christ's first coming and the ushering in of the new covenant: Jesus' life, ministry and death on earth approximately 2,000 years ago. 1 Peter 4:17, then, is speaking about an event that was happening in that very time, the purging out of His own people.