His chest is as hard as a rock, as hard as a lower millstone!
Cross References
Job 41:23The folds of his flesh are tightly joined; they are firm and immovable.
Job 41:25When Leviathan rises up, the mighty are terrified; they withdraw before his thrashing.
Treasury of Scripture
His heart is as firm as a stone; yes, as hard as a piece of the nether millstone.
as hard
Isaiah 48:4
Because I knew that thou art obstinate, and thy neck is an iron sinew, and thy brow brass;
Jeremiah 5:3
O LORD, are not thine eyes upon the truth? thou hast stricken them, but they have not grieved; thou hast consumed them, but they have refused to receive correction: they have made their faces harder than a rock; they have refused to return.
Zechariah 7:12
Yea, they made their hearts as an adamant stone, lest they should hear the law, and the words which the LORD of hosts hath sent in his spirit by the former prophets: therefore came a great wrath from the LORD of hosts.