Now it came to pass in the days when the judges ruled, that there was a famine in the land. And a certain man of Bethlehemjudah went to sojourn in the country of Moab, he, and his wife, and his two sons. When the judges ruled - We know not under what judge this happened; some say under Ehud, others under Shamgar. See the preface.
There was a famine - Probably occasioned by the depredations of the Philistines, Ammonites, etc., carrying off the corn as soon as it was ripe, or destroying it on the field.
The Targum says: "God has decreed ten grievous famines to take place in the world, to punish the inhabitants of the earth, before the coming of Messiah the king. The first in the days of Adam; the second in the days of Lamech; the third in the days of Abraham; the fourth in the days of Isaac; the fifth in the days of Jacob; the sixth in the days of Boaz, who is called Abstan, (Ibzan), the just, of Beth-lehem-judah; the seventh in the days of David, king of Israel; the eighth in the days of Elijah the prophet; the ninth in the days of Elisha, in Samaria; the tenth is yet to come, and it is not a famine of bread or of water but of hearing the word of prophecy from the mouth of the Lord; and even now this famine is grievous in the land of Israel."