Our lives are limited and not eternal by nature. It it through the sacrifice of Christ that we are granted eternal life. Psalm 49:8-9 says, 8 The ransom for a life is costly, no payment is ever enough – 9 that he should live on forever and not see decay. Back in the days of this Psalm, slaves could only be set free by being redeemed or ransomed (someone paying the price); it was a costly endeavor. But through Christ, He paid the price and set each of us free if we simply accept His gift of eternal salvation.