To practice the cardinal virtue of Temperance is to moderate the passions with reason. The virtue of Chastity is an apprenticeship in self-mastery. A person gains self-mastery by moderating the passions and directing them towards virtue, with the help of reason.
But here’s something to remember, (and something I tend to forget), and that is “reason” in this sense isn’t just an intellectual matter. Reason isn’t just in the mind, it is also in the heart. We can learn reason through religious study which can aid us in tempering the passions, but a deeper “reasoning” comes from God who speaks to our hearts.
God can speak to us at anytime, but I think He can speak the clearest when we visit Him in the Blessed Sacrament. This is where God can teach our hearts and this form of “reason” is indispensable. Religious study is important, but it is more important to not forget all things come from God. He is the one who gave us our intellect in the first place.
God is our teacher and we are His students. But not everything He wishes to teach us can be found in books.
“Jesus, I Trust In You”