Who is able to understand the gospel that Christ died for sinners?
Only individuals old enough to understand right and wrong, recognize they are sinners, and need salvation can understand the gospel that Christ died for them. Infants cannot believe or understand it. After hearing and believing, God seals them with the Holy Spirit of promise.
Les explains that this verse contradicts what many have been taught from infancy, but it does not address infants because an infant cannot believe or understand the gospel. The gospel is for someone old enough to understand right and wrong, to know they are a sinner needing salvation, and to believe that Christ died for them. After hearing and believing, God seals them with the Holy Spirit of promise. Les also notes Peter, near the end of his ministry, acknowledged the long suffering of our Lord is salvation.