It wasnarrated from Abu Hurairah that the Messenger of Allah (ﷺ)said:
'Do not anticipate Ramadan by fasting one or two days before,except for a man who has a habitual pattern of fasting, in which caselet him fast." (ES)
English reference (ES): Vol. 1, Book 7, Hadith 1650 (ES)
Arabic reference (ES): Book 7, Hadith 1719 (ES)