Ave Maria Meditations
Since all people cannot study science, a brief law has been given by our Lord, so that it can be known by all, and no one because of ignorance can be excused from its observance; and this law is the law of Divine Love.
The law of Divine Love produces in man four very desirable things:
First, it causes spiritual life in him, for it is clear that the one loved is naturally in the mind of the one loving, and therefore whoever loves God has God in him … Even the nature of love is such that it transforms the lover into the beloved. Wherefore if we love evil and earthly things, we become sinful and restless. But if we love God, we become divine, or Godlike … The soul operates virtuously and perfectly, when it operates through charity, by which God dwells in it, for without charity, the soul does not rightly operate.
Secondly, charity causes the divine commandments to be observed. Gregory says, “Never is the love of God a burden, for it does great things wherever it exists. Moreover if work is a failure, or despised, there divine love is not present. Hence, an evident sign of charity is promptitude in observing the divine commandments. For we have seen that the lover does great and difficult things for the sake of the beloved.”
The third thing which love accomplishes is that it becomes a stronghold against adversities. For to the one having charity, no adverse circumstance can injure him, but on the contrary, adversities become useful to him … Moreover adversities and trials become delightful to the one loving God, as we clearly see from everyday examples among us.
The fourth thing which charity does for us is that it leads us to happiness. For only to those having charity is eternal happiness promised; yea more, without charity, all other things are as nothing. Be it remembered therefore, that according to our degree of charity, will be our degree of eternal happiness; and not according to any other virtue.
St. Thomas Aquinas