'Written in the Book' in the Bible

and he went into all the Jordan-district preaching a baptism of repentance for the remission of sins ??4 as it is written in the book of the sayings of the prophet Isaiah, The voice of one who cries in the desert, 'Make the way ready for the Lord, level the paths for him.

As it is written in the book of the words of Esaias the prophet, saying, The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight.