C. F. Keil and Franz Delitzsch on Lamentations 3:7

Lam 3:7

God has hedged him round like a prisoner, cut off all communication from without, so that he cannot escape, and He has loaded him with heavy chains. This figure is based on Job 19:8 and Hos 2:8. גּדר בּעדי, "He hath made an hedge round me," does not suggest prison walls, but merely seclusion within a confined space, where he is deprived of free exit. "I cannot go out," as in Psa 88:9. The seclusion is increased by fetters which are placed on the prisoner. נחשׁת, "brass," for fetters, as in German and English, "irons," for iron chains.