Psalms 105:18 - Matthew Poole's English Annotations on the Holy Bible

Heb. his soul came into iron; which seems to be added emphatically to aggravate his imprisonment, and to show how grievous it was to his very soul, which must needs sympathize with his body, and moreover was greatly vexed to consider both the great injury which was done to him, and yet the foul and public scandal which lay upon him.