Alma 42:24

for behold, justice exerciseth all his demands, and also mercy claimeth all which is her own; and thus, none but the truly penitent are saved.

Fairness gets everything it demands. Mercy gets everything that’s hers. So only those who truly repent are saved.

Justice makes all its demands, and mercy claims all that belongs to her. In the end, only the truly repentant are saved.