Dont see how OT & NT agree & Q about Jesus

Q: I've read the Old Testament and the New Testament and from what I grasp, they don't seem to agree. According to the Old Testament Israel is God's son, Israel is to be a nation of priests, they are God's chosen people, and there is no Savior but God. Yet according to the New Testament Jesus is the son, believers are priests, believers are the chosen ones, and Jesus is the Savior. Help!

A: Your pastor or Sunday school teacher is the first place you should go to to ask a Bible question. To help you today tho ☺️, here is a summary guide. 

Israel spoke Hebrew, Romans spoke Greek. Jesus Redeemer Title in Hebrew is Messiah, in Greek it is Christ. So you as a non Israelite/non Jew, likely wouldn't realize that when you read the Bible in English... those are both the same word. The difference also is the OT shrouds him in mystery, the NT reveals him openly. 

At the right time in mans timeline Jesus came. 

Galatians 4:4-5 tells us, "But when the set time had fully come, God sent his Son, born of a woman, born under the law, to redeem those under the law, that we might receive adoption to sonship."

To answer your Question: 

Read Genesis 3. It points to Jesus in v 3:15.

This verse is referred to as the Protoevangelium, which means "first gospel." It states: "And I will put enmity between you and the woman, and between your offspring and hers; he will crush your head, and you will strike his heel."

This passage foreshadows the coming of Jesus and the ultimate victory over sin and Satan. The reference to the "offspring" of the woman is a prophecy of Jesus, who would come to defeat evil.

While the most direct reference to Jesus is found in Genesis 3:15, the concept of sacrifice is implied later in the narrative, pointing to the promised Messiah, & is seen all through the OT. After Adam and Eve sinned, they became aware of their nakedness and tried to cover themselves with fig leaves. 

Genesis 3:21 states:

"The LORD God made garments of skin for Adam and his wife and clothed them."

This act of God providing garments of skin indicates the first instance of sacrifice in the Bible, symbolizing the need for a blood sacrifice to cover sin. It foreshadows the ultimate sacrifice of Jesus, whose death and resurrection provide for taking away for humanity's sins [believers] & restores us to God. 

Thus, both the promise of a Savior and the reference to sacrifice in Genesis set the stage for the understanding of redemption through Christ as revealed and fulfilled in the NT.

Romans 16:25-26

"Now to him who is able to establish you in accordance with my gospel, the message I proclaim about Jesus Christ, in keeping with the revelation of the mystery hidden for long ages past, but now revealed and made known through the prophetic writings by the command of the eternal God, so that all the Gentiles might come to the obedience that comes from faith."

Colossians 1:26-27

"The mystery that has been kept hidden for ages and generations, but is now disclosed to the Lord’s people. To them God has chosen to make known among the Gentiles the glorious riches of this mystery, which is Christ in you, the hope of glory."

Ephesians 3:3-5. "That is, the mystery made known to me by revelation, as I have already written briefly. In reading this, then, you will be able to understand my insight into the mystery of Christ, which was not made known to people in other generations as it has now been revealed by the Spirit to God’s holy Apostles and prophets."

1 Timothy 3:16

"Beyond all question, the mystery from which true godliness springs is great: He appeared in the flesh, was vindicated by the Spirit, was seen by angels, was preached among the nations, was believed on in the world, was taken up in glory."

These passages collectively emphasize the revelation of God's plan through Christ. They highlight that what was once a mystery—God’s inclusive plan for salvation for both Jews and Gentiles—has now been made known through the apostles and through the Spirit. 

These verses articulate the deep theological truth that Christ embodies the fulfillment of God's redemptive plan, making it accessible to all people, [who obey the Gospel].

The Bible is in total agreement and it has no contradictions & no disagreements. Difficult areas (sure) but those are easily cleared up. 

The Bible is all about Jesus from Genesis to Revelation. It explains: Man sinned, death entered, and God promised a Savior to take away mans sin [for believers] so they can live in fellowship with Him now and in eternity. Jesus fulfilled that promise. When we step thru deaths door ["the wages of sin is death but the free gift of eternal life is through Jesus our Lord"] we enter eternity to be with Him (in a sin free eternal place). 

God saved the OT believers by their faith in the Messiah [Jewish word for "Christ" in Greek]. All before Israel (even Adam & Eve) were saved this way. God chose a people [who didnt deserve it] (which is what "Grace" means)... "to be a light to the World" to point them to the Messiah [& they failed... and later (by Jesus era) they falsely thought it was only about their special salvation & no one else]. Jesus arrived, corrected them, showed salvation was for all humanity and replaced Israels leadership with the 12 and all believers. We are a royal priesthood of believers who go and proclaim the Gospel to the World. NeedGod.com

Here is more on the Old Testament 

Here is info on the Bible in a nutshell