1 Jn 4:14
And we have seen and do testify that the Father sent the Son to be the Saviour of the world.
Religionist deny this apostolic testimony, for they make this saving purpose of the world to be a mere possibility, and not actual saving of the world. . The purpose of the incarnation is the salvation of sinners 1 Tim 1:15
15This is a faithful saying, and worthy of all acceptation, that Christ Jesus came into the world to save sinners; of whom I am chief.
If He saved only ten sinners, He accomplished the purpose of the Father, that's Saving the World.
But When John says that Christ is the Savior of the world, he is simply telling us that the grace of God is not limited to the nation of Israel alone, but that God has an elect people from the Gentiles He is going to save. God sent his Son to save men and women out of the fallen mass of humanity, Gentiles as well as Jews. Christ came to save guilty sinners John 3:14-18, The Lord Jesus Christ is the only Savior of the world Jn 4:42
And said unto the woman, Now we believe, not because of thy saying: for we have heard him ourselves, and know that this is indeed the Christ, the Saviour of the world.
Acts 4:12
12 Neither is there salvation in any other: for there is none other name under heaven given among men, whereby we must be saved.
Under heaven is the scope of this saving purpose of Jesus Christ, He has accomplished world wide Salvation in saving all of Gods elect from every nation under heaven Rev 5:9-10
9 And they sung a new song, saying, Thou art worthy to take the book, and to open the seals thereof: for thou wast slain, and hast redeemed us to God by thy blood out of every kindred, and tongue, and people, and nation;
10 And hast made us unto our God kings and priests: and we shall reign on the earth.