Where do people get the idea that there will be 7 years of tribulation?

In Daniel 12:7  "a time, times, and an half" has been interpreted as 3 and 1/2 years, which is half of the 7 year tribulation period.  Chapter 11 talks about the antichrist. 

Also, Revelation 12:6 mentions 1,260 days which I think is 3 and 1/2 years also. 

It is not to be found in scripture. People for some strange reason see things that arent there when reading scripture. They put words into Gods mouth that he never once uttered and then claim "God said it!" 

Gods word says "ten days tribulation"

Rev 2:10 Fear none of those things which thou shalt suffer: behold, the devil shall cast some of you into prison, that ye may be tried; >>>and ye shall have tribulation ten days:<<< be thou faithful unto death, and I will give thee a crown of life.

Days here is Greek hēmera meaning "period of time" - not literal 24 hour days 

See the biblical and historical "ten days of tribulation"

The Ten Primitive Persecutions

http://www.bibleprobe.com/10persecutions.htm

Ten great persecutions occurred under the reigns of the following Roman emperors (approximate dates of their reigns in parentheses)--

Nero (54-68 AD)

Domitian (81-96)

Trajan (98-117)

Marcus Aurelius (161-180)

Septimius Severus (193-211)

Maximinus (235-238)

Decius (249-251)

Valerian (253-260)

Aurelian (270-275)

Diocletian (284-305)

From the scriptures. There will actually be seven years of GREAT Tribulation. There is no pre-trib rapture either. If you're not here until the end you are dead.

From misinterpretation of the Bible. That is where Protestants get all their false beliefs.

I haven't seen anything about seven years of tribulation. If someone says there is, then give the Bible Book, Chapter, and verses.

A person can know many truths by reciting the rosary every day with care.

Seven years, mercifully reduced to half of that (42 months) with the last 6 months being the most "exciting". All in the Book of Revelation.

It's maybe mentioned once in the Book of Daniel but some think it's 3.5 years, not seven. Rapture stupids jumped on this and incorporated it into their mythology about the end of the world. You can find all sorts of cray cray blogs and preachers shouting themselves hoarse over this one. But nobody seems able to actually, um, pin down any year when this begins so...mm. 

the book of Daniel.

...but CHRIST shortened this time. (later)

this is easy to see when you study it.

Revelation also shows this as well.

the time? (hint)

Rev 12?

time = 1

times = 2

half time = 1/2 

= YEARS