The message of the Last Judgment calls men to conversion while God is still giving them "the acceptable time, . . . The day of salvation." It inspires a holy fear of God and commits them to the justice of the Kingdom of God. It proclaims the "blessed hope" of the Lord's return, when he will come "to be glorified in his saints, and to be marvelled at in all who have believed."
Source: Catechism of the Catholic Church (Vatican.va)