What books are Jesus, Paul and Nephi talking about below?
Jesus answered and said unto them, Ye do err, not knowing the scriptures, nor the power of God.
Search the scriptures; for in them ye think ye have eternal life: and they are they which testify of me.
And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus.
All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
That the man of God may be perfect, throughly furnished unto all good works.
(2 Timothy 3:15–17)
And upon these I write the things of my soul, and many of the scriptures which are engraven upon the plates of brass. For my soul delighteth in the scriptures, and my heart pondereth them, and writeth them for the learning and the profit of my children.
(2 Nephi 4:15)
A process of elimination quickly establishes that the books to which all these positive comments are attached is the Old Testament. They were the scriptures during Christ’s ministry, since the New Testament wasn’t written yet. They were still the scriptures when Paul was writing, particularly since here he’s talking about those Timothy knew as a child. And Nephi’s access to the scriptures is via the Brass Plates, a collection very close to what we know as the Old Testament, since the writings that went into the Book of Mormon also weren’t written yet. Many of the times that the scriptures (and their positive effects upon us) are mentioned in holy writ, it is the Old Testament that is being spoken of. For “the law of the Lord is perfect, converting the soul: the testimony of the Lord is sure, making wise the simple” (Psalm 19:7).