Look through the scriptures on the falling away from sound doctrine - the apostasy - and see if a scripture mentions that it is the church which is to the fall away .Luke 13: 18-21 mentions the kingdom of God in talking about the leavening that is to happen.
Matthew 24: 11-12: "And many false prophets shall rise, and shall deceive many.
12. And because iniquity shall abound, the love of many shall wax cold."
Churches often do not teach that many false prophets will arise. Often it is said that one anti-Christ will
arise to begin the falling away at the tribulation.
You can use a good concordance to find texts on the false prophets. I see pseudoprophetes used at least eleven times in the New Testament. The false prophet is also found in Jeremiah and in Ezekiel. See Ezekiel 13: 2-4. The false prophet is one who speaks out of his own heart, rather than speaking revelations given to him by the Lord. And the false prophet deceives those people into accepting his false doctrines and this is the origin of the falling away of II Thessalonians 2: 3-7. Just as there is a spirit of anti-Christ (I John 4: 3), there must also be a spirit of the false prophet. The spirit of anti-Christ denies that Christ, as God, came in the flesh, and the spirit of anti-Christ can also in a more subtle way diminish the work of Christ. The false prophet is defined in Matthew 24: 5 - many false prophets will acknowledge that there is a Christ, but will deceive many. They teach another Gospel and therefore another Jesus (II Corinthians 11: 4).
Revelation 13: 11-18, on the second beast, is heavily metaphoric. The second beast - the false prophet - represents the many false prophets of Matthew 24: 11. In Verse 12 the false prophet causes people to worship the first beast - the one in Revelation 13: 3-8 - whose deadly wound was healed. And verse 8 says those whose names are not written in the Book of Life of the Lamb will worship that first beast, or that one head of the first beast, whose deadly wound was healed. There is also information in Revelation 13: 12-18 about the workings of the second beast, but this is in metaphoric language. This is all part of the falling away from sound doctrine in the end time.
II Thessalonians 2: 3 says "Let no man deceive you by any means: for
that day shall not come, except there come a falling away first, and
that man of sin be revealed, the son of perdition;"
I Timothy 4: 1-2 says "Now the Spirit speaketh expressly, that in the
latter times some shall depart from the faith, giving heed to seducing
spirits, and doctrines of devils;
2.Speaking lies in hypocrisy; having their conscience seared with a
hot iron;"
II Timothy 4: 3-4 says "For the time will come when they will not
endure sound doctrine; but after their own lusts shall they heap to
themselves teachers, having itching ears;
4.And they shall turn away their ears from the truth, and shall be
turned unto fables."
Then, II Peter 2: 1-3 says "But there were false prophets also among
the people, even as there shall be false teachers among you, who
privily shall bring in damnable heresies, even denying the Lord that
bought them, and bring upon themselves swift destruction.
2. And many shall follow their pernicious ways; by reason of whom the
way of truth shall be evil spoken of.
3. And through covetousness shall they with feigned words make
merchandise of you: whose judgment now of a long time lingereth not,
and their damnation slumbereth not."
"Then said he, Unto what is the kingdom of God like? and whereunto
shall I resemble it?
19. It is like a grain of mustard seed, which a man took, and cast
into his garden; and it grew, and waxed a great tree; and the fowls of
the air lodged in the branches of it.. And again he said, Whereunto
shall I liken the kingdom of God?
21. It is like leaven, which a woman took and hid in three measures of
meal, till the whole was leavened." Luke 13: 18-21
It is not real surprising that the contemporary church would not often teach that Luke 13: 18-21 is about the leavening of the Kingdom of God by false doctrines, in addition to having a luke-warm attitude (Revelation 3: 16).
The word "till" in the text of Luke 13: 21, "till the whole was leavened," indicates that this leavening of the kingdom by false doctrines occurs over time and gets worse as time goes on.
Paul's comment on leaven is important in understanding Luke 13: 18-21
"Know ye not that a little leaven leaveneth the whole lump?
7. Purge out therefore the old leaven, that ye may be a new lump, as
ye are unleavened. For even Christ our passover is sacrificed for us:"
I Corinthians 5: 6-7
How could the leavening of the Kingdom of God, "till the whole was leavened" mean that this is the
process of the growth of the Gospel of Christ over time in light of what Paul says about
leaven in I Corinthians 5: 6-7? And how could the leavening of the Kingdom be a good thing when
Christ himself tells us to beware of the leaven of the Pharisees, the Sadducees and of Herod?
Then, Matthew 16: 6 says "Then Jesus said unto them, Take heed and
beware of the leaven of the Pharisees and of the Sadducees." And Mark
8: 15 warns to "Take heed, beware of the leaven of the Pharisees, and
of the leaven of Herod."