I’m struggling with something you said. You said “He said doctrine would become distorted via the church.” Where does it say the Church will distort doctrine? Paul called the church the pillar and bulwark of truth.
Jesus uses multiple parables in Matthew Chapter 13 that speak to this. Paul's comment concerns the true church that is comprised of genuine not counterfeit Christians. Revelation speaks to the fact that there is a true and false Christianity. In the Word the true church/bride of Christ is depicted as a virgin and a false one is represented by a Harlot. (Rev. 17)
Matthew 13:31-32
The leaven - false doctrine (v. 33). The mustard seed illustrates the false outward expansion of the kingdom, while the leaven illustrates the inward development of false doctrine and false living. Throughout the Bible, leaven is a symbol of evil. It had to be removed from the Jewish homes during Passover (Ex 12:15-19; 13:7). It was excluded from the sacrifices (Ex 34:35), with the exception of the loaves used at the Feast of Pentecost (Lev 23:15-21). But there the loaves symbolized Jews and Gentiles in the church, and there is sin in the church.
Jesus used leaven to picture hypocrisy (Luke 12:1), false teaching (Matt 16:6-12), and worldly compromise (Matt 22:16-21). Paul used leaven to picture carnality in the church (1 Cor 5:6-8) as well as false doctrine (Gal 5:9). Sin is like leaven (yeast): It quietly grows, it corrupts, and it "puffs up" (1 Cor 4:18-19; 5:2; 8:1). It would seem that making the growth of the leaven a picture of the spread of the Gospel throughout the world would violate the meaning of this important symbol. It would also contradict the other parables.
Satan has worked hard to introduce false doctrine and false living into the ministry of the Word of God. From the very early days of the church, true believers have battled false doctrine and hypocrisy. How sad it is that some churches and schools that were once true to the Word have turned from the truth to fables. "Prove all things; hold fast that which is good" is sound counsel (1 Thess 5:21).
The kingdom of heaven began with the sowing of the Word of God in the hearts of men. Much of the seed did not bear fruit; but some was fruitful. Satan opposed the work of God by sowing counterfeit Christians, by encouraging a false growth, and by introducing false doctrine. It would seem that Satan is winning. But the test is at the end of the age, not during the age.
(from The Bible Exposition Commentary)