Psalm 49 - Redeeming the Life of Another

7 No one can redeem the life of another or give to God a ransom for them— 

8 the ransom for a life is costly, no payment is ever enough— 

9 so that they should live on forever and not see decay. 

As you read more of the psalm you see that the writers (the sons of Korah) understand that everyone dies. The wise, the senseless, the wealthy, all who trust in themselves - all end up with the same fate - dead and decaying in the grave.

But they had this hope

15 But God will redeem me from the realm of the dead; he will surely take me to himself. 

What they didn't know was how God would fulfill verse 15. 

Galatians 4:

4 But when the fullness of the time came, God sent forth His Son, born of a woman, born under the Law, 

5 so that He might redeem those who were under the Law, that we might receive the adoption as sons. 

Yes. The ransom of a life is costly. It cost God the life of His Son, Jesus Christ. 

Here's the Gospel in a nutshell.

1 Corinthians 5:1 Now I make known to you, brethren, the gospel which I preached to you, which also you received, in which also you stand, 2 by which also you are saved, if you hold fast the word which I preached to you, unless you believed in vain. 3 For I delivered to you as of first importance what I also received, that Christ died for our sins according to the Scriptures, 4 and that He was buried, and that He was raised on the third day according to the Scriptures,

Bottom line:

Those without Christ are just like those described in Psalm 49.

Jesus came to redeem us from the grave.

He did that by dying in our place - He was buried and He rose again on the third day.