Is error in doctrine always sin? Zophar once said the self evident to Job, “My doctrine is pure, and I am clean in thine eyes.” Also self evident from our Lord is to “beware of the leaven (doctrine) of the Pharisees and of the Sadducees”. Biblically, right doctrine is pure and good, and wrong doctrine is condemned and avoided, even when it is an error. There is little if any room in the Bible for false teaching or false teachers being anything but sin in the sight of a holy God. We all make errors in doctrine, and growth in Christ includes seeing that and moving on. The mercy of God covers our blindness. But that doesn’t mean that that blindness may not be called sin. I believe that ‘error’ is a synonym for sin in the context of your question. Your question could be rephrased, “is doctrinal sin, sin?” The answer is yes. In Romans 3:23, all have sinned. The word sin is defined as: 1) to be without a share in 2) to miss the mark 3) to err, be mistaken 4) to miss or wander from the path of uprightness and honour, to do or go wrong 5) to wander from the law of God, violate God’s law, sin Sin includes to err. In the Old Testament, the first use of this idea I found in a quick study was Le 4:2 “Speak unto the children of Israel, saying, If a soul shall sin through ignorance <07684> against any of the commandments of the LORD concerning things which ought not to be done, and shall do against any of them”. Here again, sin is synonymous with error. The Hebrew word sh@gagah (07684) is defined: 1) sin, sin of error or inadvertence, inadvertent sin 1a) error Comparing other NT and OT uses of these words strengthens this thought. In Matthew 15, Jesus calls such as err in doctrine hypocrites. v.9, “But in vain they do worship me, teaching for doctrines the commandments of men.” Since the Bible calls error in doctrine sin in both believers and infidels, it would seem that the word “always” in your question would fit. I’d be open to hear an exception? Is doctrinal sin, sin? I believe it is. In Christ, Tim Clifton