That Jesus, true God and true man, was crucified, buried, and resurrected for our salvation.
Now, brothers and sisters, I want to remind you of the gospel I preached to you, which you received and on which you have taken your stand. By this gospel you are saved, if you hold firmly to the word I preached to you. Otherwise, you have believed in vain. For what I received I passed on to you as of first importance: that Christ died for our sins according to the Scriptures, that he was buried, that he was raised on the third day according to the Scriptures [...] But Christ has indeed been raised from the dead, the firstfruits of those who have fallen asleep. For since death came through a man, the resurrection of the dead comes also through a man.
(1 Corinthians 15:1-4, 20-21)
That we receive the benefits of Christ’s redemption through faith. Such faith is offered to us by the Holy Spirit. As children we are "born again" through the gift of Holy Baptism.
Repent and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins. And you will receive the gift of the Holy Spirit. (Acts 2:38)
Then, through Christian instruction, we come to understand and confess our faith.
If you declare with your mouth, “Jesus is Lord,” and believe in your heart that God raised him from the dead, you will be saved. (Romans 10:9)
That all of our salvation is by the Grace of God. We cannot earn our way to heaven by what we do.
For it is by grace you have been saved, through faith —and this is not from yourselves, it is the gift of God — not by works, so that no one can boast. (Ephesians 2:8-9)