Reliance yes,but no where is Isaiah teaching:
The church is accountable to scripture.
No where!
BTW: The Jews did not have a fixed canon at the time of Isaiah. So what Bible are you referring to?
The Jews had the law and the prophets which was scripture. A little more complete in Jesus day.
Acts 13:15
And after the reading of the law and the prophets the rulers of the synagogue sent unto them, saying, Ye men and brethren, if ye have any word of exhortation for the people, say on.
Acts 24:14
But this I confess unto thee, that after the way which they call heresy, so worship I the God of my fathers, believing all things which are written in the law and in the prophets:
Acts 28:23
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.
Luke4
16 And he came to Nazareth, where he had been brought up: and, as his custom was, he went into the synagogue on the sabbath day, and stood up for to read.
17 And there was delivered unto him the book of the prophet Esaias. And when he had opened the book, he found the place where it was written,
18 The Spirit of the Lord is upon me, because he hath anointed me to preach the gospel to the poor; he hath sent me to heal the brokenhearted, to preach deliverance to the captives, and recovering of sight to the blind, to set at liberty them that are bruised,
19 To preach the acceptable year of the Lord.
20 And he closed the book, and he gave it again to the minister, and sat down. And the eyes of all them that were in the synagogue were fastened on him.
21 And he began to say unto them, This day is this scripture fulfilled in your ears.
The bible that Jesus read was called the Law and the Prophets and yes God’s church was subject to it because it talked about Jesus.