https://www.youtube.com/watch?v=xIl4bkmTg6Q&t=199s

Sound doctrine is important because the gospel is a sacred trust, and we dare not tamper with God’s communication to the world. Our duty is to deliver the message, not to change it. Jude conveys an urgency in guarding the trust: “I felt I had to write and urge you to contend for the faith that was once for all entrusted to the saints” (Jude 1:3; see also Philippians 1:27). To “contend” carries the idea of strenuously fighting for something, to give it everything you’ve got. The Bible includes a warning neither to add to nor subtract from God’s Word (Revelation 22:18-19). Rather than alter the apostles’ doctrine, we receive what has been passed down to us and keep it “as the pattern of sound teaching, with faith and love in Christ Jesus” (2 Timothy 1:13).