One of the important rules of worship that has an inseparable connection with prayer is the rule of ablution. The verse containing the quality of performing ablution, which is called the ablution verse, is found in Sura Māʾida (verse 6); A sura that was revealed at the end of the life of the Prophet Muḥammad in Medina. We know that prayer was legalized in Mecca. Also, according to some evidence, the Prophet always prayed with ablution from the beginning of his Prophethood. Therefore, it is reasonable to ask why the ruling on ablution for prayer and the quality of performing it was revealed late at the end of the prophethood and in Sūra al-Māʾida. Commentators have paid less attention to this issue, and have rarely asked why. In the present study, the scattered comments of some commentators are examined and criticized. The hypothesis of this study is that the legislation of ablution was carried out through a non-Qurʾānic revelation at the beginning of the Prophet's mission in Mecca; But since some Muslims during the period of Medina did not pay attention to the invalidities of ablution or to performing ablution or performing it correctly, especially for the morning prayer, and sometimes they attended the prayer of the Prophet without ablution or with an incomplete ablution, and also, in order to emphasizing the necessity of paying attention to ablution and two other purifications (al-Ghusl and al-Tayammum), the verse of ablution was placed in the last years of the Prophetic period, and in a chapter before the last chapter of the Qurʾān.