The Bible is quite clear that Jesus came to this earth PRIMARILY as the Savior of the world. We can take a look at some key Scriptures:
But while he thought on these things, behold, the angel of the Lord appeared unto him in a dream, saying, Joseph, thou son of David, fear not to take unto thee Mary thy wife: for that which is conceived in her is of the Holy Ghost. And she shall bring forth a son, and thou shalt call his name JESUS: for he shall save his people from their sins. (Mt 1:20,21)
Jesus (Yeshua or Yahshua) means God is our salvation. So Jesus = Savior.
The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world. (John 1:20)
Christ came as the Lamb of God to take away the sin of the world. See Isaiah 53. And this Lamb was prepared from before the foundation of the world (1 Pet 1:18-20).
This is a faithful saying, and worthy of all acceptation, that Christ Jesus came into the world to save sinners; of whom I am chief. (1 Tim 1:15)
And that simply confirms the above, since it points to the cross.
I don't know who has been trying to mislead you, but Isaiah spoke of penal substitution long before Paul. Hundreds of years before Paul: But he was wounded for our transgressions, he was bruised for our iniquities: the chastisement of our peace was upon him; and with his stripes we are healed. All we like sheep have gone astray; we have turned every one to his own way; and the LORD hath laid on him the iniquity of us all. (Isa 53:5,6).
And without penal substitution, the cross of Christ would be meaningless. You would be required to pay for your own sins. People can come up with all kinds of new-fangled ideas (or ancient heresies) but the Word of the Lord stands forever.