“Doctrine” is a dirty word for a lot of Christians. Many are oblivious, often throwing around phrases like, “All this talk about doctrine… isn’t the important thing knowing God?” and, “There’s nothing worse than theology in the hands of the untrained.”
Maybe I got hit in the head too much when I was a kid, but the whole point of doctrine is for us to know God—all of the teaching we receive is about God and the Christian life is doctrine.
The Bible is doctrine.
Paul wrote to his disciple, Timothy, about this very issue:
If you put these things before the brothers, you will be a good servant of Christ Jesus, being trained in the words of the faith and of the good doctrine that you have followed. Have nothing to do with irreverent, silly myths. Rather train yourself for godliness; for while bodily training is of some value, godliness is of value in every way, as it holds promise for the present life and also for the life to come. The saying is trustworthy and deserving of full acceptance. For to this end we toil and strive, because we have our hope set on the living God, who is the Savior of all people, especially of those who believe.
Command and teach these things. Let no one despise you for your youth, but set the believers an example in speech, in conduct, in love, in faith, in purity. Until I come, devote yourself to the public reading of Scripture, to exhortation, to teaching. Do not neglect the gift you have, which was given you by prophecy when the council of elders laid their hands on you. Practice these things, immerse yourself in them, so that all may see your progress. Keep a close watch on yourself and on the teaching [or doctrine]. Persist in this, for by so doing you will save both yourself and your hearers.
1 Tim 4:6-16, emphasis added