The claim that the Prophet ﷺ fasted every Monday because he was born on that day, and that Mawlid (the Prophet’s birthday) should be celebrated through fasting and worship, is not entirely accurate. While the Prophet ﷺ did fast on Mondays, this was not to commemorate his birth but for other reasons. Firstly, Monday was the day he received the first revelation (Muslim 1162), and it was also the day when the deeds of the people were presented to Allah (Tirmidhi 747). Furthermore, the Prophet ﷺ did not follow his fast with any celebrations nor did he encourage such practices.
It is important to note that there is no definitive narration from the six major hadith collections specifying the exact date of the Prophet’s ﷺ birth. The Arab tradition generally recognized individuals by their death dates, which led to varying opinions on the specific date of his birth. These opinions include various dates in the month of Rabīʿ al-Awwal, such as the 2nd, 5th, 7th, 8th, 9th, 10th, and 12th, with the 12th being the most commonly held view.
The Prophet ﷺ’s fasting on Mondays was a practice of devotion, not a commemoration of his birth, and there is no basis in his actions or teachings for celebrating the Mawlid as an Eid.