Roman Catechism 27.2

Chapter 27 — Part III: The Decalogue — The Fourth Commandment

Section 2. Importance Of Instruction On The Fourth Commandment — The advantages arising from the present subject can scarcely be expressed in words; for not only does it bring with it its own fruit, and that in the richest abundance and of superior excellence, but it also affords a test of our obedience to and observance of the first Commandment. He that loveth not his brother whom he seeth, says St. John, how can he love God whom he seeth not? In like manner, if we do not honour and reverence our parents whom we ought to love next to God and whom we continually see, how can we honour or reverence God, the supreme and best of parents, whom we see not? Hence we can easily perceive the similarity between these two Commandments.