Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.057A.

Section : Making Ghusl upon entering Makkah.

It is preferable for whoever wants to enter Makkah to perform ghusl. It is reported that Ibn ‘Umar, when going to Makkah, would spend the night in Tawa, and would enter Makkah during the day. He mentioned that the Prophet, upon whom be peace, also used to do this. (Related by al-Bukhari and Muslim.) Ibn al-Munzhir said, “All of the scholars say it is preferred to perform ghusl upon entering Makkah, but if one does not do so, there is no expiation for him to make. Most of them say that the regular ablution is sufficient.