“And when We said to you,” meaning: We inspired you, “that your Lord has encompassed the people,” meaning: the people of Mecca; that is: He protects you from them, so they shall not reach you until you have conveyed the message from Allah. “And We did not make the vision which We showed you,” meaning: what Allah showed him on the night he was taken on the Night Journey (Isra'), and it was not a dream, but rather a direct witnessing, “except as a trial for the people,” meaning the polytheists, when the Prophet (peace be upon him) informed them of his journey to Jerusalem and his return in a single night, the polytheists denied it and were tested thereby. “And the accursed tree in the Quran,” He says: and We did not make the accursed tree in the Quran except as a trial for the people. Al-Hasan and Mujahid said: It is the Zaqqum tree. When it was revealed, Abu Jahl called for dates and butter and said: "Come, let us 'zaqqum' (eat greedily); we know no Zaqqum other than this!"

Al-Hasan said: And His saying, “the accursed in the Quran,” means that those who eat from it are cursed in the Quran. He said: “And We warn them,” by the Zaqqum tree, “but it increases them,” our warning them with it and with other things, “in nothing but great transgression.”

Surah Al-Isra, from verse 61 to verse 64.