1) Where did Jesus give instructions that the Christian faith should be based exclusively on a book?

Jesus commanded the Christian faith be based solely upon God's Word which exists only in scripture.

It is written:

Deuteronomy 4:2 Ye shall not add unto the word which I command you, neither shall ye diminish ought from it, that ye may keep the commandments of the LORD your God which I command you.

Jesus through Moses (2 Tim 3:16) commanded the Word of God be undiminished by traditions of men, precisely because God intended we follow His commandments, above those of men.

As the Word of God (John 1:1) it is Jesus who speaks as YHWH LORD in the Old Testament John 12:41 Isaiah 6:1; Zechariah 12:3; John 1:1 with Genesis 3:8.

Therefore it is certain Jesus ordained a clear divide separate His Word....from those of men, so that His Word have supreme authority.

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The times of this ignorance God winked at; but now commandeth all men every where to repent:

Behold, I stand at the door, and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me.-kjv