God "desires all men to be saved and to come to the knowledge of the truth": that is, of Christ Jesus. Christ must be proclaimed to all nations and individuals, so that this revelation may reach to the ends of the earth:
God graciously arranged that the things he had once revealed for the salvation of all peoples should remain in their entirety, throughout the ages, and be transmitted to all generations.
Source: Catechism of the Catholic Church (Vatican.va)