This sermon expounds on Ephesians 4:25-32, arguing that believers, as new creations in Christ, must align their actions, speech, and thoughts with their renewed identity. The central message emphasizes that God is concerned not merely with external behavior but with the heart, which dictates both words and attitudes. The text highlights the duty to speak truth and edify others, avoiding falsehood, gossip, and malicious speech, while also addressing the need to manage anger and replace sinful thoughts with those that please God. Drawing on the Westminster Larger Catechism, the exposition provides specific applications for the Ninth Commandment, urging listeners to pursue integrity, kindness, and spiritual growth through the power of the Holy Spirit.