2 Nephi 2:26

And the Messiah cometh in the fulness of time, that he might redeem the children of men from the fall. And because that they are redeemed from the fall, they have become free forever, knowing good from evil; to act for themselves, and not to be acted upon, save it be by the punishment of the law, at the great and last day, according to the commandments which God hath given.

The Messiah will come to save people from the fall. Because they are saved from the fall, they are free forever. They know good from evil. They can choose for themselves. They are not controlled unless they are punished on the last day for breaking God’s rules.

The Messiah will come when the time is right to rescue humanity from the fall. Because they’re rescued from the fall, they become free forever, knowing good from evil, able to act for themselves instead of being acted upon—except for the punishment of the law on the final judgment day, according to God’s commands.