99 Consequently, as the onslaughts of these uncontrolled passions cannot in any way be lessened, unless the spirit first shows a humble compliance of duty and reverence towards its Maker, it is above all and before all needful that those who are joined in the bond of sacred wedlock should be wholly imbued with a profound and genuine sense of duty towards God, which will shape their whole lives, and fill their minds and wills with a very deep reverence for the majesty of God.
Source: Casti Connubii (Vatican.va)