Is the abrogation of turning towards Al-Aqsa Mosque not an abrogation, because it is an abrogation of a ruling, which is not known whether the Prophet, peace and blessings be upon him, did it through his own ijtihad or by Allah's command, given that revelation is not confined to the Quran?

The Prophet, peace and blessings be upon him, faced Jerusalem for a little over ten months after his arrival in Medina. This was by the command of Allah Almighty, and this is the view of the majority of scholars.

Scholars have differed on how Jerusalem was faced. Some said it was based on personal judgment and ijtihad, while others said he had a choice between it and the Kaaba. However, the most preponderant view is that it was by the command of Allah Almighty.

Then Allah Almighty abrogated this command and ordered him to face the Kaaba. This was the first abrogation in the Qur'an. Scholars have based this on the saying of Allah Almighty: "And We did not make the Qiblah which you used to face except that We might make evident who would follow the Messenger from who would turn back on his heels."

Assuming that facing Jerusalem was by the Prophet's ijtihad, Allah's approval of it at that time indicates its legality. The subsequent command to face the Kaaba would then be a matter of abrogation, which is what the jurists have used as evidence for the abrogation of the Sunnah by the Qur'an.