In this sermon, the speaker emphasizes the importance of following God's commands and teachings. They acknowledge that there may not be anything new in the message, as these instructions have been given for thousands of years. The sermon focuses on three principles: the purity of the church, the purity of individual Christians, and the need to spread the gospel to others. The speaker references 2 Timothy 4:1-3, where Paul charges Timothy to preach the word and teach the truth. The sermon also highlights the danger of taking God's relationship for granted and acting inappropriately. Additionally, the speaker mentions the importance of relationships in revealing the character of both individuals and nations.