A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
2 Kings (2 Samuel)
sa2 0:0THE FIRST AND SECOND BOOKS OF SAMUEL. The two were, by the ancient Jews, conjoined so as to make one book, and in that form could be called the Book of Samuel with more propriety than now, the second being wholly occupied with the relation of transactions that did not take place till after the death of that eminent judge. Accordingly, in the Septuagint and the Vulgate, it is called the First and Second Books of Kings. The early portion of the First Book, down to the end of the twenty-fourth chapter, was probably written by Samuel; while the rest of it and the whole of the Second, are commonly ascribed to Nathan and Gad, founding the opinion on Ch1 29:29. Commentators, however, are divided about this, some supposing that the statements in Sa1 2:26; Sa1 3:1, indicate the hand of the judge himself, or a contemporary; while some think, from Sa1 6:18; Sa1 12:5; Sa1 27:6, that its composition must be referred to a later age. It is probable, however, that these supposed marks of an after-period were interpolations of Ezra. This uncertainty, however, as to the authorship does not affect the inspired authority of the book, which is indisputable, being quoted in the New Testament (Sa1 13:14 in Act 13:22, and Sa2 7:14 in Heb 1:5), as well as in many of the Psalms.