Jesus is our Savior because through Him all mankind can be saved from the slavery of sin and be saved for everlasting life with God.
St. Paul refers to sin as a slavery. Jesus Christ is our Savior because He saved us from sin. St. Paul said, “For you did not receive the spirit of slavery to fall back into fear, but you have received the spirit of sonship. When we cry, ‘Abba! Father!’ it is the Spirit himself bearing witness with our spirit that we are children of God” (Romans 8:15-16), and “Stand fast therefore, and do not submit again to a yoke of slavery” (Galatians 5:1).