In today’s readings we hear Jesus speaking in Galilee as well as a Jewish sage named Sirach writing in Jerusalem more than a century earlier. The two of them touch upon a single truth: The words that come out of us make known the hidden thoughts within us. Speech reveals the secrets of the heart.
Sirach teaches that speaking is “the test of men” and their character (Sir 27:7). One who is upright will utter words that are truthful and encouraging to others. But one whose heart is cluttered with “refuse” will be exposed, since the “fruit” of his mouth speaks volumes about the “tree” that produces it (Sir 27:6). Sirach also compares the testing of our words to clay fired in a kiln—if properly prepared, a useful vessel emerges; but if the clay is not fully dried, it will break apart in the extreme heat (Sirach 27:5).
In a similar way, Jesus insists that a person speaks “out of the abundance of the heart” (Luke 6:45). He too compares our speech, whether good or bad, to what grows on a tree: “For no good tree bears bad fruit, nor again does a bad tree bear good fruit” (Luke 6:43).
Both readings urge us to make wholesome speech a habit. After all, much about who we are is brought to light through what we say. But there’s an additional step: The Lord is asking us to look inward, to examine our hearts and fill them with the “good treasure” that God desires.
Why do purity of heart and speech matter so much? Because, as Jesus declares elsewhere: “by your words you will be justified, and by your words you will be condemned” (Matt 12:37). They matter because they help to decide our final judgment, and this is where the Second Reading comes in. Paul reminds us that God will destroy death forever, and if we are to share in this victory and live forever with the Lord, then we must take all steps necessary to give our hearts and lips to what is good.