I heard the Prophet ﷺ say, "Whoever performs Hajj for the sake of Allah and neither speaks indecently nor commits any wrongdoing returns as pure as the day his mother bore him."
سمعت النبي ﷺ يقول: من حج لله فلم يرفث، ولم يفسق رجع كيوم ولدته أمه.
Bukhari narrated it in the chapter on Hajj (1521), and Muslim narrated it in the chapter on Hajj (1350), both from the hadith of Sayyar Abu Hakam, from Abu Hazim, from Abu Hurairah, and he mentioned it, and the wording is Bukhari's.