In spite of the holy Law that again and again their Holy God gives them - "You shall be holy, for I the LORD your God am holy" - and although the Lord shows patience for the sake of his name, the people turn away from the Holy One of Israel and profane his name among the nations. For this reason the just ones of the old covenant, the poor survivors returned from exile, and the prophets burned with passion for the name.
Source: Catechism of the Catholic Church (Vatican.va)