"My doctrine shall drop as the rain, my speech shall distil as the dew, as the small rain upon the tender herb, and as the showers upon the grass." -- Deuteronomy 32:2
Attempting to cast one of God's servants in what they imagine is an ugly light, men will some times say, "He is a doctrinal preacher," failing to realize that to people who read their Bibles, that is not a detraction but an attraction. All gospel preachers are doctrinal preachers. "Doctrine" is not an dirty word. It simply means "teaching". The doctrine of Christ is the teaching of Christ. The doctrine of the Bible is the teaching of the Bible. The Bible has much to say about doctrine. Read 2 Timothy 3:1-4:6 and Ephesians 4:11-16. Doctrine is vital to any true gospel ministry.
It is the business of every gospel preacher to give himself wholly to prayer, the study of the Word, and doctrine. And it is the duty of every gospel preacher to establish his hearers in sound doctrine, so that they be not tossed about with divers and strange doctrines. That preacher who labors in the Word and in the doctrine, Paul says, is "worthy of double honor" (1 Tim. 5:17). That means he is worthy of double the pay of any other man. He does not seek it, or even desire it; but he is worthy of it. He is to be highly esteemed in love for his work's sake (1 Thess.5:12-13).
All true doctrine is described in the Word of God as "pure doctrine" (Job 11:4), "good doctrine" (1 Tim. 4:6), and "sound doctrine" (1 Tim. 1:10). The gospel of Christ, the teaching of the Bible, is called "the doctrine of God" (Tit. 2:10), "the doctrine of Christ" (Heb. 6:1), and "the doctrine which is according to godliness" (1 Tim. 3:6).
Neither God's prophet Moses, nor his apostle Paul, nor the Lord Jesus Christ himself was embarrassed to call the doctrine of God his doctrine. So a man is in good company who openly asserts that the gospel of God's free and sovereign grace in Christ is "My Doctrine!" With Paul, I say, my doctrine is a matter of public knowledge (2 Tim. 3:10). I preach it everywhere I go, keeping back nothing. With my Savior, I say, my doctrine will bear the scrutiny of Holy Scripture (John 76:16-17). I invite all to examine and judge everything I write or preach by the Word of God. With Moses I assert that my doctrine is the joyous doctrine of song and praise to God. -- "Give ear, O ye heavens, and I will speak; and hear, O earth, the words of my mouth. My doctrine shall drop as the rain, my speech shall distil as the dew, as the small rain upon the tender herb, and as the showers upon the grass: Because I will publish the name of the LORD: ascribe ye greatness unto our God. He is the Rock, his work is perfect: for all his ways are judgment: a God of truth and without iniquity, just and right is h." (Deut. 32:1-4).