Romans 10:13 (NIV)

13 for, “Everyone who calls on the name of the Lord will be saved.

Explanation: 
For whosoever shall call ... - This sentiment is found substantially 
in Joel 2:32, "And it shall come to pass, that whosoever shall call on 
the name of the Lord shall be delivered." This is expressly applied to 
the times of the gospel, by Peter, in Acts 2:21; see the note on that 
place. To call on the name of the Lord is the same as to call on the 
Lord himself. The word "name" is often used in this manner. "The name 
of the Lord is a strong tower, etc.;" Proverbs 18:10. "The name of the 
God of Jacob defend thee;" Psalm 20:1. That is, God himself is a strong 
tower, etc. It is clear from what follows, that the apostle applies this
 
to Jesus Christ; and this is one of the numerous instances in which the 
writers of the New Testament apply to him expressions which in the Old 
Testament are applicable to God; see 1 Corinthians 1:2.

Shall be saved - This is the uniform promise; see Acts 2:21; Acts 22:16,
 "Arise, and be baptized, and wash away thy sins, calling on the name of 
the Lord." This is proper and indispensable because,

(1) We have sinned against God, and it is right that we should confess it.

(2) because he only can pardon us, and it is fit, that if we obtain pardon, 
we should ask it of God.

(3) to call upon him is to acknowledge him as our Sovereign, our Father, 
and our Friend; and it is right that we render him our homage.

It is implied in this, that we call upon him with right feelings; 
that is, with a humble sense of our sinfulness and our need of pardon, 
and with a willingness to receive eternal life as it is offered us 
in the gospel. And if this be done, this passage teaches us that all 
may be saved who will do it. He will cast none away who come in this 
manner. The invitation and the assurance extend to all nations and to people of all times.