Thus does Allah seal up the hearts of those who know not (the proofs and evidence of the Oneness of Allah i.e. those who try not to understand true facts that which you (Muhammad SAW) have brought to them)
Thus Allah seals the consciousness of the ignorant!
Sayyed Abbas Sadr-Ameli
Thus does Allah set a seal on the hearts of those who do not know
Al-muntakhab fi tafsir al-Qur'an al-Karim
Thus does Allah imprint an objectionable disposition on the hearts of those who do not realize the object of thought nor do they bring it vividly and clearly before their minds