I did this ¹  because I know how stubborn you are. Your neck muscles are like iron and your forehead like bronze. ² 

biblegateway Isa 48:4

"Because I know that you are obstinate, And your neck is an iron sinew And your forehead bronze,

Because I know that you are stubborn, and your neck is iron and your forehead bronze,

I know that you are stubborn. Like iron, you are hardheaded. Like bronze, nothing gets through your thick skull.

biblegateway Isa 48:4

For I knew how stubborn you were; the sinews of your neck were iron, your forehead was bronze.

Because I know that you are obstinate, and your neck is an iron sinew and your forehead brass,

bibleoremus Isa 48:4

Because I know that you are obstinate, and your neck is an iron sinew and your forehead brass,

Knowing your stubbornness, your neck being as stiff as iron, your brow like brass,

biblegateway Isa 48:4

Because I knew that you were obstinate, And your neck was an iron sinew, And your brow bronze,

Because I knew that thou [art] obstinate, and thy neck [is] an iron sinew, and thy brow brass;

biblegateway Isa 48:4

I did this ¹  because I know how stubborn you are. Your neck muscles are like iron and your forehead like bronze. ² 

¹ tn The words “I did this” are supplied in the translation for stylistic reasons. In the Hebrew text v. 4 is subordinated to v. 3.

² sn The image is that of a person who has tensed the muscles of the face and neck as a sign of resolute refusal.