I answer that, This or that may be more important to a thing in two ways, either because it is more essential or because it is more excellent. If the reason is because it is more excellent, then "sacrament" is in every way the most important of the three marriage goods, since it belongs to marriage considered as a sacrament of grace; while the other two belong to it as an office of nature; and a perfection of grace is more excellent than a perfection of nature. If, however, it is said to be more important because it is more essential, we must draw a distinction; for "faith" and "offspring" can be considered in two ways. First, in themselves, and thus they regard the use of matrimony in begetting children and observing the marriage compact; while inseparability, which is denoted by "sacrament," regards the very sacrament considered in itself, since from the very fact that by the marriage compact man and wife give to one another power the one over the other in perpetuity, it follows that they cannot be put asunder. Hence there is no matrimony without inseparability, whereas there is matrimony without "faith" and "offspring," because the existence of a thing does not depend on its use; and in this sense "sacrament" is more essential to matrimony than "faith" and "offspring." Secondly, "faith" and "offspring" may be considered as in their principles, so that "offspring" denote the intention of having children, and "faith" the duty of remaining faithful, and there can be no matrimony without these also, since they are caused in matrimony by the marriage compact itself, so that if anything contrary to these were expressed in the consent which makes a marriage, the marriage would be invalid. Taking "faith" and "offspring" in this sense, it is clear that "offspring" is the most essential thing in marriage, secondly "faith," and thirdly "sacrament"; even as to man it is more essential to be in nature than to be in grace, although it is more excellent to be in grace.