‘ And it came about in the days when the judges judged, that there was a famine in the land. And a certain man of Beth-lehem-judah went to sojourn in the country of Moab, he, and his wife, and his two sons.'
The famine occurred in the days of ‘the Judges' (local rulers), each of whom at various times ruled a part of Israel. There were many periods under the Judges when the land was peaceful (see Judges 3:11; Judges 3:30 etc.), and this would appear to have been one of them. If there are no gaps in the genealogy in Ruth 4:18-22 it suggests that it was probably late in that period, possibly in the time of Samuel, although some (accepting gaps in the genealogy) relate it to the famines caused by the predators in the time of Gideon (Judges 6). Whichever period we accept the famine was of sufficient severity to cause a man of Bethlehem-judah to seek refuge, with his family, in neighbouring Moab. This would involve crossing the Jordan, possibly at Jericho, and moving southwards into Moab.
“Went to sojourn --.” That is, semi-permanently as a resident alien. His intention would be to remain there until the famine was over.
“He, and his wife, and his two sons.” It was probably the need of his sons that he had in mind when he made the move, especially if, as their names suggest, they were weak and sickly. They would be in no condition to withstand famine. But one whose name declared that ‘My God is king' should never have been seeking refuge in a land that was submissive to another god (Chemosh). He was belying his name.