A private high school has instituted a “no foul language” pledge—only to female students. According to the school’s principal, the girls had been using the foulest language. (Hmm, I’m guessing the boys were guilty too!) So they were asked to raise their right hands and say: “I do solemnly swear not to use profanities of any kind within the walls and properties of Queen of Peace High School.” So, in essence, the students swore not to swear (to speak profanity).

According to Scripture, no external rule or pledge can fix the smell of foul speech. Jesus revealed that just as people know the kind of tree by the fruit it bears (Luke 6:43-44), so people know by what a person says whether his heart is pure or not. In this instruction, Jesus uses fruit to define spoken words, not a person’s works: “What you say flows from what is in your heart” (Luke 6:45).

The Savior was pointing out that if you really want to change a person’s speech, you have to go straight to the heart—not start with the mouth. A transformed heart will transform one’s speech. As David wrote, “Create in me a clean heart, O God. Renew a loyal spirit within me” (Psalm 51:10).

We can’t change our words with pledges and swearing not to swear. We eliminate bad speech by letting the Holy Spirit change our hearts. The transformation begins when we confess Jesus as Lord (1 Corinthians 12:3). It continues as we invite the Holy Spirit to fill us.

And when He does, He inspires us to sing good words about God and His works (Ephesians 5:18-19). We will also begin to thank God for everything, speak in a way that’s gracious and tactful, and use words that are instructive and edifying (Ephesians 5:20, Ephesians 4:15,29; Colossians 4:6).

NLT 365-day reading plan passage for today: Luke 12:1-21