Sklerokardia denotes a resistant inner disposition cited as the reason for divorce permission and for refusing witness.

The attested use denotes a resistant inner disposition: it is given as the reason Moses permitted divorce in Mark 10:5 and Matthew 19:8, and it is reproved alongside unbelief in Mark 16:14.

1. Resistant disposition toward instruction or witness · dominant

   In Mark 10:5 and Matthew 19:8, the accusative singular form occurs in clauses giving the reason Moses permitted divorce; the APB renders those clauses with “because of your hardness of heart.” In Mark 16:14, the same form is reproved with unbelief after the eleven had not believed those who saw him arisen.

   Mark 10:5Mark 16:14Matthew 19:8

In the Anselm Project Bible: The APB presents the term with “hardness of heart” in all three verses. Its whole-verse translation supports the contexts of divorce permission and unbelief.