What is truth? We began this book with that question, and my earnest hope is that the answer is clear by now: Truth is not any individual’s opinion or imagination. Truth is what God decrees. And He has given us an infallible source of saving truth in His revealed Word.
   For the true Christian, this should not be a complex issue. God’s Word is what all pastors and Church leaders are commanded to proclaim, in season and out of season—when it is well received and even when it is not (2 Timothy 4:2). It is what every Christian is commanded to read, study, meditate on, and divide rightly.
It is what we are called and commissioned by Christ to teach and proclaim to the uttermost parts of the earth.
   Is there mystery even in the truth God has revealed? Of course. “‘For My thoughts are not your thoughts, nor are your ways My ways,’ says the Lord.” (Isaiah 55:8). In 1 Corinthians 2:16, Paul paraphrased Isaiah 340:13–1: “Who has known the mind of the Lord that he may instruct Him?”
   But then Paul immediately added this: “We have the mind of Christ.” Christ has graciously given us enough truth and enough understanding to equip us for every good deed—including the work of earnestly contending for the faith against deceivers who try to twist the truth of the gospel. Although we cannot know the mind of God exhaustively, we certainly can know it sufficiently to be warriors for the cause of truth against the lies of the kingdom of darkness.
   And we are commanded to participate in that battle. God Himself sounded the call to battle when His spirit moved Jude to write his short epistle and it permanently entered the canon of Scripture. This is not a duty any faithful Christian can shirk. Earthly life for the faithful Christian can never be a perpetual state of ease and peace. That’s why the New Testament includes so may descriptions of the Christian life as nonstop warfare: Ephesians 6:11–18; 2 Timothy 2:1–4; 2 Timothy 4:7; 2 Corinthians 6:7; 10:3–5; 1 Thessalonians 5:8. I hope by now you understand that those unwilling to join the fight against untruth and false religion are no true friends of Christ.

—John MacArthur, The Truth War (Thomas Nelson, 2007), 183–184.