As soon as one adds anything to faith alone in Christ alone it voids the faith in Him. Scripture providing us His Word is sufficient for all good works in the life of every believer in God’s Plan.
The doctrine you seek to attack is the doctrine of the sufficiency of Scripture.
True, and Scripture provides for the church and teachers, (Luke 10:16) etc. which authority SS is misconstrued as rejecting, but Scripture is alone the supreme objective authority by which all truth claims are tested.
“Others said, This is the Christ. But some said, Shall Christ come out of Galilee? Hath not the scripture said, That Christ cometh of the seed of David, and out of the town of Bethlehem, where David was?” (John 7:41-42)
“They answered and said unto him, Art thou also of Galilee? Search, and look: for out of Galilee ariseth no prophet.” (John 7:52)
(As the prophets had declared that the Messiah was to come from the tribe of Judah, and from the family of David, and should be born in the city of Bethlehem, [Mic. 5:2] these Jews, imagining that Christ had been born in Galilee, concluded that he could not be the Messiah. Had they examined the matter a little farther, they would have found that he had his birth exactly as the prophets had foretold. - Clarke)
“And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself. “ (Luke 24:27)
“And Paul, as his manner was, went in unto them, and three sabbath days reasoned with them out of the scriptures,” (Acts 17:2)
“These were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so.” (Acts 17:11)
“And to this agree the words of the prophets; as it is written, After this I will return, and will build again the tabernacle of David, which is fallen down; and I will build again the ruins thereof, and I will set it up: That the residue of men might seek after the Lord, and all the Gentiles, upon whom my name is called, saith the Lord, who doeth all these things.” (Acts 15:15-17)
“For he mightily convinced the Jews, and that publickly, shewing by the scriptures that Jesus was Christ.” (Acts 18:28)
“And when they had appointed him a day, there came many to him into his lodging; to whom he expounded and testified the kingdom of God, persuading them concerning Jesus, both out of the law of Moses, and out of the prophets, from morning till evening.” (Acts 28:23)
The apostles did add (by writing or sanction) to the yet open canon, (2Pet. 3:16) these being, like Moses, powerfully attested to by supernatural signs (2Cor. 12:12) and holy life, while their preaching was manifestly Scriptural and could pass that test. (Acts 17:11) However, the canon being close, to hold another source of Divine revelation to be of equal authority is to essentially add to the canon, and the subjective is proved by the objective.