Hebrews 13:9 reminds us, “It is good for the heart to be strengthened by grace.” Sound doctrine fortifies believers against false teaching and trials. Calvin wrote that only the knowledge of God can sustain us. Sproul said sound doctrine enables us to stand firm to the end. Doctrine is not just knowledge—it is God’s means of strengthening His people to endure in faith and holiness.

Day 15 of our 30-day study focuses on the doctrine of God, emphasizing His holiness and sovereignty. Scripture reveals the majesty of God’s character, setting Him apart as holy and ruling over all creation. Doctrine teaches us to tremble in awe and rest in His sovereign rule.

Paul warns in 2 Timothy 4:3–4 that people will not endure sound doctrine but will seek teachers to satisfy itching ears. This is the spirit of pragmatism—choosing what “works” or feels good over what is true. Calvin warned that whenever men turn aside from God’s Word, they “turn to vanity.” Sound doctrine, not pragmatism, builds faithful churches. The truth may not always please, but it always saves.

False teachers distort God’s truth and cause doctrinal drift (2 Peter 2:1–3). They often cloak their lies with words that sound spiritual but deny the Master who bought us. John Owen warned that error is most dangerous when dressed in truth. The church must cling to sound doctrine to resist deception. Where truth is abandoned, holiness crumbles; but where doctrine is held fast, the church stands firm.

Without doctrine, the church loses her anchor. Paul warns that many will reject sound teaching and chase after teachers who “tickle their ears” (2 Tim. 4:3). History shows that when truth is abandoned, error multiplies and holiness declines. Sound doctrine guards against chaos. To cherish doctrine is to cherish God Himself, for His truth alone gives clarity, stability, and unity to His people.

Doctrine is simply teaching — not speculation, not human opinion, but God’s truth revealed in His Word. Paul urges leaders to hold firmly to sound doctrine (Titus 1:9). R.C. Sproul reminds us, “Everyone’s a theologian” (Everyone’s a Theologian, p. 1). The only question is whether we are faithful to God’s teaching or swayed by man’s ideas. The church stands firm when she treasures doctrine.

Doctrine is God’s safeguard for the gospel. Paul warned the Galatians not to accept “another gospel” (Gal. 1:6–9). The church must guard the message of salvation by grace alone through faith in Christ alone. As John Owen noted, error always seeks to corrupt the gospel at its root. Doctrine protects, ensuring the good news is proclaimed clearly, faithfully, and powerfully to each generation.

The apostle Paul repeatedly reminds the church to hold fast to sound teaching. He urged Timothy, “Retain the standard of sound words which you have heard from me” (2 Tim. 1:13). Again, he warns that “the time will come when they will not endure sound doctrine” (2 Tim. 4:3).