The Old Testament or The Writings of Moses and the Prophets. The Name, Old Testament, was coined by Melito of Sardis in the 2nd century AD.
The Old Testament consists of thirty-nine books according to the Protestant reckoning but only twenty-four according to the Jewish reckoning. The books are the same; the difference is in the way they are divided.
Protestant Bible
The division of the Protestants’ Bible is as follows: seventeen historical books: Genesis-Esther: five poetical books Job-Song of Solomon: seventeen prophetical books: Isaiah-Malachi.
Hebrew Division
The Hebrew Bible numbers these as twenty-four: The Torah or law contains five books, Genesis-Deuteronomy; The Prophets contain eight books, Joshua, Judges, Samuel, Kings, Isaiah, Jeremiah, Ezekiel, and the twelve minor prophets are grouped into one book; The Writings or Kethubim contain eleven books, Psalms, Proverbs, Song of Solomon, Ruth, Lamentations, Ecclesiastes, Esther, Daniel, Ezra-Nehemiah, and Chronicles.
The Hebrew Bible combined 1 and 2 Samuel, 1 and 2 Kings, and 1 and 2 Chronicles. The twelve minor prophets were combined into one book. Josephus numbered the books as twenty-two by attaching Ruth to Judges and Lamentations to Jeremiah. Thus, the books are identical. The only difference is in the way they are divided.
The Old Covenant was a conditional or bilateral agreement that God made with the Nation of Israel.