2 Chronicles 34:14 "The Book of the Law of Yahweh" is a document title and should be capitalized because there is no better way (yet) to graphically represent titles.
2 Chronicles 34:15 "The Book of the Law" is a document title and should be capitalized because there is no better way (yet) to graphically represent titles.
2 Chronicles 34:30 "The Book of the Covenant" is a document title and should be capitalized because there is no better way (yet) to graphically represent titles.