To repeat: "Behold the Lamb of God who take away the sins of the world."
Seems pretty clear, which part are you having trouble with?
Ok, here's my answer: I think it means that everyone before 33 AD avoided Hell but that after 33 AD you had to be a Christian to stay out of Hell. Am I correct?
And I thought that from 33 AD on, the gift had to be accepted by free will in order to avoid Hell.