The Old Testament
The Gospel of John 1 clearly emphasizes that Jesus Christ as God the Son existed at the Creation itself. In other words, when God created the world, it was Jesus Christ creating the world. In fact, the Holy Trinity created the world.
The Holy Trinity is one God in 3 persons: God the Father, God the Son, and God the Holy Spirit. Thus, everything that God (or "Yahweh") did in the Old Testament, the three persons of the Holy Trinity did. In other words, wherever you read God or LORD ("Yahweh") in the Old Testament, you can read "the Holy Trinity". Thus, when God created the world, Jesus as God the Son created the world.
In the same way, when God destroyed Sodom and Gomorrah and killed every human being in those cities on the charge of crime against God of homosexuality, it was Jesus as the Son of God who destroyed Sodom and Gomorrah and killed every living human being in those cities. Yes, Jesus did it.
A person who cannot accept this Truth statement is probably not a born-again, true Christian. Of course, God is the Final Judge, but God gave us criteria by which we can discern who are true Christians and who are not, because God's work needs to be done on earth and this information is very important.
Understanding how the Old Testament points to Jesus the Radical of the Bible and history is, in fact, critical to personal salvation and to eternal life.