Corrupted is too strong a word. Jesus' teachings were never completely lost, and I don't buy the idea that somehow transmission of his authority broke down. But the Church did change did move from a Jewish to a Greek mindset. They also almost completely lost Jesus' concept of the Kingdom of God, and started emphasizing saving people from hell. Saving people is part of Jesus' message, but the overall shape changed. The biggest change, though, was ethics. Purity, particularly sexual purity, became a focus. Jesus didn't use the concept, as it was characteristic of the Pharisees.
Which fallacious premise has been refuted, and means that you see the NT church as revealed in Acts - Rev. as deviating from Christ, thus relying on the discredited red-letter hermeneutic, as if the words in Acts - Rev. were not from Christ to His Spirit, which they were.
Saving souls from Hell and personal purity certainly were a primary focus of Christ, even in the gospels alone. He even warns of Hell more than most of the epistles. Holiness or Hell.
For the Son of man is come to seek and to save that which was lost. (Luke 19:10)
And if thy hand offend thee, cut it off: it is better for thee to enter into life maimed, than having two hands to go into hell, into the fire that never shall be quenched: Where their worm dieth not, and the fire is not quenched. And if thy foot offend thee, cut it off: it is better for thee to enter halt into life, than having two feet to be cast into hell, into the fire that never shall be quenched: Where their worm dieth not, and the fire is not quenched. And if thine eye offend thee, pluck it out: it is better for thee to enter into the kingdom of God with one eye, than having two eyes to be cast into hell fire: Where their worm dieth not, and the fire is not quenched. (Mark 9:43-48)
And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell. (Matthew 10:28)
And thou, Capernaum, which art exalted unto heaven, shalt be brought down to hell: for if the mighty works, which have been done in thee, had been done in Sodom, it would have remained until this day. (Matthew 11:23)
Woe unto you, scribes and Pharisees, hypocrites! for ye compass sea and land to make one proselyte, and when he is made, ye make him twofold more the child of hell than yourselves. (Matthew 23:15)
Ye serpents, ye generation of vipers, how can ye escape the damnation of hell? (Matthew 23:33)
And in hell he lift up his eyes, being in torments, and seeth Abraham afar off, and Lazarus in his bosom. And he cried and said, Father Abraham, have mercy on me, and send Lazarus, that he may dip the tip of his finger in water, and cool my tongue; for I am tormented in this flame. (Luke 16:23-24)
Then he said, I pray thee therefore, father, that thou wouldest send him to my father’s house: For I have five brethren; that he may testify unto them, lest they also come into this place of torment. (Luke 16:27-28)
And shall cast them into a furnace of fire: there shall be wailing and gnashing of teeth. (Matthew 13:42)
And shall cast them into the furnace of fire: there shall be wailing and gnashing of teeth. (Matthew 13:50)
But the children of the kingdom shall be cast out into outer darkness: there shall be weeping and gnashing of teeth. (Matthew 8:12)
Then shall he say also unto them on the left hand, Depart from me, ye cursed, into everlasting fire, prepared for the devil and his angels: (Matthew 25:41)
And these shall go away into everlasting punishment: but the righteous into life eternal. (Matthew 25:46)
But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery. (Matthew 5:32)
And he said unto him, Why callest thou me good? there is none good but one, that is, God: but if thou wilt enter into life, keep the commandments. He saith unto him, Which? Jesus said, Thou shalt do no murder, Thou shalt not commit adultery, Thou shalt not steal, Thou shalt not bear false witness, Honour thy father and thy mother: and, Thou shalt love thy neighbour as thyself. (
Matthew 19:17-19)
Jesus saith unto her, Go, call thy husband, and come hither. The woman answered and said, I have no husband. Jesus said unto her, Thou hast well said, I have no husband: For thou hast had five husbands; and he whom thou now hast is not thy husband: in that saidst thou truly. (
John 4:16-18)
"For from within, out of the heart of men, proceed evil thoughts, adulteries, fornications, murders, Thefts, covetousness, wickedness, deceit, lasciviousness, an evil eye, blasphemy, pride, foolishness: All these evil things come from within, and defile the man. (
Mark 7:21-23)
The Son of man shall send forth his angels, and they shall gather out of his kingdom all things that offend [which word is used by Him in reference to fornication in
Revelation 2:14], and them which do iniquity [transgression of the law in
1 John 3:4]. (
Matthew 13:41)
And if thine eye offend thee, pluck it out: it is better for thee to enter into the kingdom of God with one eye, than having two eyes to be cast into hell fire: (
Mark 9:47)
But I say unto you, That whosoever shall put away his wife, saving for the cause of fornication, causeth her to commit adultery: and whosoever shall marry her that is divorced committeth adultery. (
Matthew 5:32)
And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female, And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh? Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder. (
Matthew 19:4-6)
When Jesus had lifted up himself, and saw none but the woman, he said unto her, Woman, where are those thine accusers? hath no man condemned thee? She said, No man, Lord. And Jesus said unto her, Neither do I condemn thee: go, and sin no more. (
John 8:10-11)
Woe unto you, scribes and Pharisees, hypocrites! for ye make clean the outside of the cup and of the platter, but within they are full of extortion and excess. (
Matthew 23:25)