For the Christian the day of death inaugurates, at the end of his sacramental life, the fulfillment of his new birth begun at Baptism, the definitive "conformity" to "the image of the Son" conferred by the anointing of the Holy Spirit, and participation in the feast of the Kingdom which was anticipated in the Eucharist - even if final purifications are still necessary for him in order to be clothed with the nuptial garment.
Source: Catechism of the Catholic Church (Vatican.va)