At the dedication of the Temple of Solomon, when the Ark was brought into the most holy place, there was nothing in it but the two tables, 1 Kings 8:9; and therefore when the Philistines took the Ark, they took out of it the book of the Law, and the golden pot of Manna, and Aaron’s Rod. And this and other losses in the desolation of Israel, by the conquering Philistines, might give occasion to Samuel, after some respite from those enemies, to recollect the scattered writings of Moses and Joshua, and the records of the Patriarchs and Judges, and compose them in the form now extant.
The book of Ruth is a history of things done in the days of the Judges, and may be looked upon as an addition to the book of the Judges, written by the same author, and at the same time. For it was written after the birth of David, Ruth 4:17, 22; and not long after, because the history of Boaz and Ruth, the great grandfather and great grandmother of David, and that of their contemporaries, could not well be remembered above two or three generations. And since this book derives the genealogy of David from Boaz and Ruth, and omits David’s elder brothers and his sons; it was written in honor of David, after he was anointed King by Samuel, and before he had children in Hebron, and by consequence in the reign of Saul.
It proceeds not to the history of David, and therefore seems to have been written presently after he was anointed.
They judge well who ascribe to Samuel the books of Joshua, Judges, and Ruth. Samuel is also reputed the author of the first book of Samuel, till the time of his death. The two books of Samuel cite no authors, and therefore seem to be originals. They begin with his genealogy, birth and education, and might be written partly in his life-time by himself, or his disciples the Prophets at Naioth in Ramah, 1 Samuel 19:18, 19, 20; and partly after his death by the same disciples.