You are right that Christ did change and/or abolish some Old Testament precepts...
Since he was God he had the authority to change the Law because he is the lawgiver and gives the law its force and authority and content.
Right. He abolished them as part of his New Covenant of mercy. We are no longer demanded to follow all the Old Testament rules. There was a fundamental shift. I don't think that, for example, Jesus ever said that you can never stone prostitutes or that you don't have to follow any of the rules of ritual cleanliness. But He did stop a prostitute from being stoned, and his example serves as how to act in other cases. It was an overall approach Christ wants us to apply, and that's why we don't follow the rules of ritual cleanliness, for example. Jesus asked us to basically show maximum mercy and forgiveness in applying rules or not following them. So you don't have to stone prostitutes or cane children or fools or bad women, even when the Old Testament says to do it. That explains why Jesus intervened to spare the prostitute.
Seeing the Old Testament as being fundamentally in opposition with the New Testament is an Old Heresy called Marcionism. Usually this heresy is manifested in todays environment by statements such as: "I like the God of the New Testament who talks about mercy and love but I can't stand the angry God of the Old Testament."
It is not true that if you no longer are forced to follow the Old Testament that you reject God like Marcion. The opposite is true. Tertullian rejected Marcion by saying that God told us in Jeremiah that He would give us a "new covenant". Tertullian concluded that by fulfilling his promise and disposing of the old covenant, God proves that He is the God that promised He would put it aside.
That's why Paul writes in Hebrews 8 that God made the Old Law obsolete.
Christ himself said that he did not come to abolish the law but to fulfill it: "Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them." Matthew 5:17.
Right. In a way, He did not "abolish" the law- he fulfilled its requirements so that we no longer are forced to follow it. He made it obsolete like Paul said.
Christ paid for our sins under the Law by dying on the cross. He paid the debt required by the law. If people were to ignore mercy and beat children viciously with canes, then it would not be following the idea that God has taken people's guilt for their sins from them.
The only texts considered Scripture at that time was the Old testament.
No, the New Testament is sometimes also called "the scriptures" in the Bible. See: 2 Peter 3:15-16 There is another place where the Bible calls the New Testament scripture.
Whether you see Christ as a figure in opposition to the law or as someone who reoriented and/or superseded it is a matter of interpretation , but I think Christ's own words indicate for the later position and I think the interpretation of the Church is in agreement with mine.
The position of Orthodoxy, and for that matter traditional Protestantism and Catholicism, is that Christ "superseded" the Old Testament. Christian living by grace is put above the demands of the law.
Proverbs is a book of practical advice for everyday living I don't see how anything Christ did or said that would indicate we should now ignore it, if you do please show it to me.
Wisdom is found on the lips of the discerning, but a rod is for the back of one who has no sense.
Penalties are prepared for mockers, and beatings for the backs of fools.
Beating people for being "foolish" is not a demand from Christianity.
Here is another problem:
(29:19) "A servant will not be corrected by words: for though he understand he will not answer."
This is implying to beat servants to force them to answer, because words don't suffice to correct their mistakes.
The spirit of forgiveness of the New Testament overrides the penal aspects of the Old Testament. That is why Christ says to be merciful as your Father in heaven has been merciful. That's why He says that the Merciful will be shown Mercy.
The idea of Christianity is that the Old Testament says to levy some punishments, like stoning adulterers, but we are supposed to supersede those laws with mercy as a way of Christian living.