怎樣才能戒除粗俗的言語？一所中學鼓勵學生做出「不講髒話」的承諾。學生們宣誓﹕「我鄭重承諾，在我們學校的範圍內，絕不說任何粗言穢語。」這是一種崇高的願景，但我們從聖經看到，耶穌認為任何一個外在的條規或承諾，都不能改變說粗言穢語的習慣。

若要除去我們口中污穢的言語，首先要更新我們的內心。正如根據一棵樹所結的果子，人們就能判斷這是一棵什麼樹（路加福音6章43-44節）。耶穌說，你我的言語是一個極具說服力的指標，可以向人表明我們的心是否隨從耶穌，是否行在祂的道路上。果子可以代表一個人的言語，「因為心裡所充滿的，口裡就說出來」（45節）。基督指出，如果我們真的想改變口中所說的話，就必須倚靠祂的幫助，先專注於改變自己的內心。

如果內心沒有改變，那麼口頭上的承諾根本無法遏制由心發出的粗言穢語。我們只有先相信耶穌，並邀請聖靈充滿我們，才能除掉口中的粗言穢語（哥林多前書12章3節；以弗所書5章18節）。祂會改變我們的內心，激勵並幫助我們不斷地感謝上帝（20節），並向別人說鼓勵和勸勉的話（4章15、29節；歌羅西書4章6節）。

How do you eliminate foul language? A high school chose to institute a “no foul language” promise. The students took an oath, saying: "I do solemnly promise not to use profanities of any kind within the walls and properties of [our school].” This was a noble effort, but, according to Jesus, no external rule or pledge can ever cover the odor of foul speech.

Removing the stench of the words that come from our mouths begins with renewing our hearts. Just as people recognize the kind of tree by the fruit it bears (Luke 6:43-44), Jesus said that our speech is a convincing indicator of whether our hearts are in tune with Him and His ways or not. Fruit stands for a person’s speech, “for the mouth speaks what the heart is full of” (v. 45). Christ was pointing out that if we really want to change what’s coming out of our mouths, we first have to focus on changing our hearts as He helps us.

External promises are useless to curb the foul language that comes forth from an untransformed heart. We can only eliminate foul speech by first believing in Jesus (1 Corinthians 12:3) and then inviting the Holy Spirit to fill us (Ephesians 5:18). He works within us to inspire and help us to continually offer thanks to God (v. 20) and to speak encouraging and edifying words to others (4:15, 29; Colossians 4:6).