Q. 29. Why is the Son of God called Jesus, that is a Saviour?
Because He saveth us, and delivereth us from our sins; and likewise, because we ought not to seek, neither can find salvation in any other.
 Matthew 1:21;  Acts 4:12.
Q. 30. Do such then believe in Jesus the only Saviour, who seek their salvation and welfare of saints, of themselves, or anywhere else?
They do not; for though they boast of Him in words, yet in deeds they deny Jesus the only deliverer and Saviour; for one of these two things must be true, that either Jesus is not a complete Saviour; or that they, who by a true faith receive this Saviour, must find all things in Him necessary to their salvation.
 1 Corinthians 1:13, 31; Galatians 5:4;  Colossians 2:20; Isaiah 9:6–7; Colossians 1:19–20.
The name “Jesus” was not chosen by Mary or Joseph, but by the Lord Himself. Shortly after the Lord was conceived in Mary’s womb, the angel of the Lord appeared to Joseph, and said to him:
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).
Heidelberg Catechism >