Because I knew that thou art obstinate, and thy neck is an iron sinew, and thy brow brass;
Because I knew that thou (art) obstinate - Hebrew, hard, (Deuteronomy 9:27; Ezekiel 3:7, margin.)
And thy neck is an iron sinew - inflexible (Acts 7:51).
And thy brow brass - shameless as a harlot, (see Jeremiah 6:28; Jeremiah 3:3; Ezekiel 3:7, margin.)