I will cause them to eat the flesh of their sons - This was literally fulfilled when Jerusalem was besieged by the Romans. This also the prophet might have had in view.
Matthew Henry
Concise Bible Commentary
The prophet must give notice of ruin coming upon Judah and Jerusalem. Both rulers and ruled must attend to it. That place which holiness made the joy of the whole earth, sin made the reproach and shame of the whole earth. There is no fleeing from God's justice, but by fleeing to his mercy.
SDA Bible Commentary (limited)
Volume 1-7
9. Cause them to eat. See Deut. 28:49-57; Lam. 2:20. Josephus records one instance where a mother ate her own child because of the terrible famine in Jerusalem during the siege of Titus in a.d. 70 (Wars vi. 3. 4).