In the days of Shamgar son of Anath, in the days of Jael, the highways were deserted and the travelers took the byways.
Here, I. Deborah describes the distressed state of Israel under the tyranny of Jabin, that the greatness of their trouble might make their salvation appear the more illustrious and the more gracious (Jdg 5:6): From the days of Shamgar, who did something towards the deliverance of Israel from the Philistines, to the days of Jael, the present day, in which Jael has so signalized herself...
Commenting on Judges 5:6-11
In the days of Shamgar, the son of Anath,.... Of whom see Jdg 3:31; who succeeded Ehud as a judge, but lived not long, and did not much; at least wrought not a perfect deliverance of the children of Israel; but during his time till now, quite through the twenty years of Jabin's oppression, things were as they are after described: in the days of...
The song proceeds in these verses to describe the sad condition of the country, the oppression of the people, and the origin of all the national distress in the people's apostasy from God. Idolatry was the cause of foreign invasion and internal inability to resist it.