Hello scrdsckpppt:
It depends on what you believe about the nature and authority of the Old Testament as to whether or not we can show you that Jesus is God's last 'revelation' to man directly.
You see, if you believe the Old Testament and that the Ten Commandments are authoritive and from God, then it can be shown that Jesus came to complete or fulfill the Law (Matthew 5:17), and thus, must be of God.
What do I mean by the phrase 'Jesus came to complete the Law?' By fulfilling (or completing) the law, Christ satisfied it's requirements in our place. In other words, the 'required' obedience is accomplished in Him. Therefore, in Christ do we keep all the law faithfully, and cannot be accused. In this way, we are no longer judged by any of the everlasting laws, for we are under the Grace of God. The law doesn't condemn us as it does for those who are not under God's Grace.
Anyway, moving on... The Old Testament Laws were not designed to give men eternal life, but rather to open their eyes to see just how sinful and depraved we really are and just how much we need a Saviour from our sins. The Bible tells us that if we even break the Ten Commandments
once that we have fallen short of God's standards and thus deserve to face God's justice, which Paul describes that the wages of sin is death (Romans 6:23). What are God's standards, you might ask? Perfection. You're right if you think,
Well who in the world can live up to those standards? Answer: no one, except for Jesus. That's why we need a Saviour.
If you believe that you are a sinner totally and hopeless depraved and separated from God because of your sins, then you need someone else to come along and 'build a bridge' between a holy and just God and sinful man. However, this person Himself must not be sinful other wise He would be in the same situation as us (being condemned by our sins and separated from a holy God) and hence cannot help us.
An Answers In Genesis article called
Why Is There Death And Suffering? by Ken Ham and Dr Jonathan Sarfati explains how this can be done a lot better than I ever could:
The only way for us to restore our life with God is if we are able to come to Him with the penalty paid for our sin. Leviticus 17:11 helps us to understand how this can be done. It says, The life of the flesh is in the blood. Blood represents life. The New Testament explains that without the shedding of blood there is no remission [of sins] (Hebrews 9:22). God makes it clear that, because we are creatures of flesh and blood, the only way to pay the penalty for our sin is if blood is shed to take away our sin.
In the Garden of Eden, God killed an animal and clothed Adam and Eve as a picture of a covering for our sin. A blood sacrifice was needed because of our sin. The Israelites sacrificed animals over and over again; however, because Adams blood does not flow in animals, animal blood, though it could temporarily cover our sin, could never take it away. The Hebrew word translated atonement is kaphar, which means cover.
The solution was Gods plan to send His Son, the Second Person of the triune Godhead, the Lord Jesus Christ, to become a mana perfect manto be a sacrifice for sin. In the person of Jesus Christ, our Creator God stepped into history (John 1:114) to become a physical descendant of Adam, called the last Adam (1 Corinthians 15:45), born of a virgin. Because the Holy Spirit overshadowed His mother (Luke 1:35), He was a perfect man, one without sindespite having been tempted in every way that we are (Hebrews 4:15)who thus could shed His blood on a cross for our sin.
Because mankinds first representative headAdamwas responsible for bringing sin and death into the world, the human race can now have a new representativethe last Adamwho paid the penalty for sin. No sinner could pay for the sins of others, but this last AdamJesus Christwas a perfect man. God in human flesh was able to bear the sins and sorrows of the world.
Because our sins separated us from God, Jesus came and paid the penalty (or curse) for our sins (which is death). He took the penalty which should rightly have been ours at the hands of a righteous judge, and bore it in His own body on the cross. All who believe in Jesus Christ as Lord and Saviour are received back to God to spend eternity with Him. This is why Jesus is God's final 'revelation' to man; He did what we cannot do, He built the bridge between holy God and sinful humanity that no one else could build because all other men are sinful and thus need a Saviour themselves. We are that depraved that there is nothing we can do to even help save ourselves reach heaven. This is why God sent His Son, to do what we can't. He lived a perfect and sinless life and thus became a sacrifice for our sins. When we come to Him in faith, He will forgive us and justify (or declare righteous) us before the Father.
It is because Jesus has fulfilled the requirements of the Old Testament law and paid the price for my sins and forgiven me of my sins that I do not believe in any other prophet claiming to be of God who claim that there is another way to get to heaven. Firstly, logically, if there were another way, why would God send His Son to Earth to suffer a horrible death? That makes no sense to me. Secondly, Jesus has done all what is required to reach heaven - place our faith in Him and ask Him to forgive us of our sins and we're justified and sealed by the Holy Spirit. This is why I reject Muhammad's message, for example - although he claims that his message is based on the Old Testament and the Gospels, he misses the fact that the work of Jesus completed the Old Testament Law. Thus there is no need to 'build' more requirements on top of it (e.g. believing that Muhammad was a 'prophet').
For more information on why Jesus' sacrifice was necessary, please see:
Why Is There Death And Suffering? by Ken Ham and Dr Jonathan Sarfati of Answers In Genesis, available on-line at <answersingenesis.org/docs2002/death_suffering.asp>.
For more information on the Old Testament Law and how Jesus' life and death fulfilled it and this means for us, please see:
The Law And How It Is Fulfilled In Christ by Tony Warren on The Mountain Retreat, available on-line at <mountainretreatorg.net/faq/oldlaw.html>.
