For those who don't know, The Law, is the Penteteuch or the first five books of The Old Testament. The Law of Moses (aka, Mosaic Law) are all the regulations around the commandments called The Law of God, which are The Ten Commandments. (Mosaic Law is found in the second through fifth books of The Old Testament and dots all the "i's" and crosses all the "t's" in how to live and worship God. The regulations were so many that "love of God" was lost in theology! It is my belief that supersessionism, The Law of Christ, which fulfills The Law of God, is a reintroduction of "love" into the theology of the Jews.
With that said, the theology of the Pharisees, not only failed to save the people, but it damned them. Therefore, theology without sound doctrine leads to damnation and my friend was right! Does doctrine save? In fact what is doctrine? It's "beliefs that are taught as true". Doctrine isn't "fact", but is believed to be so. People who follow the "doctor" (origin of the word "doctrine") have the doctrine of whom they follow. Christians follow the "good doctor", Jesus, and their doctrine (what they believe is true) must be what Jesus taught! "Sound doctrine" is teaching accurately the precepts of Christ.
Titus 2:1 "But speak thou the things which become sound doctrine: 2 That the aged men be sober, grave, temperate, sound in faith, in charity, in patience. 3 The aged women likewise, that they be in behaviour as becometh holiness, not false accusers, not given to much wine, teachers of good things..."Why do these two lists of things become "sound doctrine"? They follow the truths spoken by Jesus and demonstrate love of God and love of others, the two commands missed in Mosaic Law, but were there all the time in God's Law. As you can see from the list of commandments, love was there all the time:
Genesis 20:6 "And shewing mercy unto thousands of them that love me, and keep my commandments.""Showing mercy" is "loving others". Loving God is crucial in this passage and to show that love of others and God, we are to "keep my commandments". Compare that to what Jesus said:
John 14:15 "If ye love me, keep my commandments."In a nutshell, this verse is the supersession to The Law. It's why Jesus came and what salvation is about! It's The Law of Christ! John 14:15 is doctrine. It is truth said by Jesus. It is how we have the "sound doctrine" spoken of in the Book of Titus passages above! However, "sound doctrine" is understanding truth. The truth, though, is in what Jesus actually did! He died for us all by the shedding of his blood. That's "truth" and is "doctrine". It's what we must believe to be saved. Hence, although doctrine leads to salvation, it doesn't save, but without "sound doctrine" we just don't get saved.
Augustine, Luther and Calvin did a great job of putting "love" into doctrine, but they nearly took The Law of God out of their doctrine. As Jesus didn't come to replace The Law, but to fulfill it, Calvin and his predecessors replaced it! Christianity is much like gourmet food: It's not enough to stand back and love it, but to show that love, we must partake of it! That's what Jesus said: love me and show it by "doing". What are we to do? Keep God's Law!
What I just wrote is "theology". It is the study of God. Because I know much of God's word doesn't make me a Christian! However, if I belief the truth that I've learned in theology, then if I accept it and obey, that leads to salvation. It's still Jesus who saved me, but his doctrine is why I'm saved! The best example of this follows:
Acts 8:27 "An he arose and went: and, behold, a man of Ethiopia, an eunuch of great authority under Candace queen of the Ethiopians, who had the charge of all her treasure, and had come to Jerusalem for to worship, 28 Was returning, and sitting in his chariot read Esaias the prophet. 29 Then the Spirit said unto Philip, Go near, and join thyself to this chariot. 30 And Philip ran thither to him, and heard him read the prophet Esaias, and said, Understandest thou what thou readest? 31 And he said, How can I, except some man should guide me? And he desired Philip that he would come up and sit with him. 32 The place of the scripture which he read was this, He was led as a sheep to the slaughter; and like a lamb dumb before his shearer, so opened he not his mouth: 33 In his humiliation his judgment was taken away: and who shall declare his generation? for his life is taken from the earth. 34 And the eunuch answered Philip, and said, I pray thee, of whom speaketh the prophet this? of himself, or of some other man? 35 Then Philip opened his mouth, and began at the same scripture, and preached unto him Jesus. 36 And as they went on their way, they came unto a certain water: and the eunuch said, See, here is water; what doth hinder me to be baptized?Philip explained to the eunuch what he had just read. Philip explained that Isaiah was speaking of Jesus way back then! The explanation of the truth is doctrine and Philip used doctrine which led to the eunuch's salvation. It was sound doctrine because it led to salvation!
37 And Philip said, If thou believest with all thine heart, thou mayest. And he answered and said, I believe that Jesus Christ is the Son of God."