Tafsir of At-Takweer 81:23

"And indeed, he saw him on the clear horizon."

He saw him—that is, by Allah, your companion, the Messenger of Allah (may Allah bless him and grant him peace), saw the noble messenger Gabriel (peace be upon him) upon a chair between the heaven and the earth in the form in which Allah the Almighty created him, possessing six hundred wings—at the clear horizon. This is the highest horizon in the direction of the east, as reported by al-Hasan, Qatadah, Mujahid, and Sufyan.

In a narration from Mujahid, it is stated that the Messenger of Allah (may Allah bless him and grant him peace) saw him toward Ji'ad, which is the east of Mecca. It has also been said that the meaning is the rising point of the head of Cancer, as it is the highest of the rising points for the people of Mecca. This vision occurred after the affair of the Cave of Hira. Ibn Shajara related that it was the western horizon of the sky, but there is no merit to this claim.

Al-Tabarani and Ibn Marduyah recorded from Ibn Abbas that he said regarding this verse: "He saw him in his true form at the Lote Tree of the Utmost Boundary (Sidrat al-Muntaha)." According to this view, "horizon" (al-ufuq) is understood to mean a "direction," and it is also said that it was named a horizon metaphorically.