Why is following God better than living a full 70 years of worldly pleasure?
Following God is better because faith in Christ brings justification, peace with God, and access into relationship with the Creator. Even if worldly pleasure lasts a full seventy years, it cannot compare to the billions upon billions of years of eternity that believers will enjoy forever and ever.
Les explains that when a person recognizes they are a child of Adam and believes the gospel—that Christ died for our sins, was buried, and rose from the dead—God does everything on their behalf. This includes justification, meaning just as if we have never sinned by taking God at His Word, and peace with God through Jesus Christ, by whom we have access by faith into a glorious state as a believer in relationship with the Creator Himself. Les contrasts the world's activities and their idea of living it up. Even if they live it to the full for a whole seventy years, that is nothing compared to the billions upon billions upon billions of years of eternity. The point is perspective: following God is not merely limiting ourselves and ignoring worldly pleasures for a few years of bliss; for believers, it is eternity forever and ever and ever.