What is the interpretation of Allah's saying: {And when you recite the Qur'an, We put between you and those who do not believe in the Hereafter a hidden veil}?

The verse in question was interpreted by Imam Al-Tabari as Allah having placed a veil between Prophet Muhammad and the polytheists who did not believe in resurrection, preventing their hearts from understanding the Qur'an and benefiting from it, as a punishment for their disbelief. This veil is the barrier. Al-Sa'di clarifies that this veil prevents them from understanding the Qur'an and submitting to the good it calls for, as a punishment for their denial of the truth and their turning away from it.