These two clauses mean nearly the same thing, said twice for emphasis, first in the negative and then in the positive. Some languages may indicate emphasis in a different way. Alternate translation: God""'s real reason for sending his Son into the world was to save it" (See: [[rc://en/ta/man/translate/figs-parallelism]])
"to punish." Usually "punish" implies that the person who has been punished is then accepted by God. When a person is condemned, he is punished but never accepted by God.