UNTO SALVATION ROMANS 1:16

What power, point does the Gospel of JESUS Christ reach or enter

unto means; indicating the point reached or entered

Salvation means  deliverance, preservation, safety, salvation

Believeth: to believe, have a mental persuasion,faith, belief, firm persuasion, 

conviction of the truth of anything, belief; in the NT of a conviction or belief respecting man’s relationship to God and divine things, generally with the included idea of trust and holy fervour born of faith and joined with it

1a) relating to God

1a1) the conviction that God exists and is the creator and ruler of all things, the provider and bestower of eternal salvation through Christ

1b) relating to Christ

1b1) a strong and welcome conviction or belief that Jesus is the Messiah, through whom we obtain eternal salvation in the kingdom of God 

persuade

1a) to persuade, i.e. to induce one by words to believe

1 Cor. 1:20-31