וַיֹּ֥אמֶר יְהוָ֖ה אֵלַ֣י לֵאמֹ֑ר רָאִ֙יתִי֙ אֶת־הָעָ֣ם הַזֶּ֔ה וְהִנֵּ֥ה עַם־קְשֵׁה־עֹ֖רֶף הֽוּא׃
Y hablóme SEÑOR, diciendo: He visto ese pueblo, y he aquí, que él es pueblo duro de cerviz:
Sforno
ובחורב הקצפתם, Moses underlines the serious nature of this negative characteristic known as “stiff-necked,” by reminding the people that even at Mount Sinai when G’d had already decided to wipe them out, (verse 14 our chapter) G’d had justified this by referring to their stiff-necked nature. He had not decreed death for them on account of a specific and horrific sin, but on account of their attitude which bode ill for the future, indicated that such a people was not capable of becoming true penitents.