Sacred art is true and beautiful when its form corresponds to its particular vocation: evoking and glorifying, in faith and adoration, the transcendent mystery of God - the surpassing invisible beauty of truth and love visible in Christ, who "reflects the glory of God and bears the very stamp of his nature," in whom "the whole fullness of deity dwells bodily." This spiritual beauty of God is reflected in the most holy Virgin Mother of God, the angels, and saints. Genuine sacred art draws man to adoration, to prayer, and to the love of God, Creator and Savior, the Holy One and Sanctifier.
Source: Catechism of the Catholic Church (Vatican.va)