Bulugh al-Maram, Book 5, Hadith 650 (In-Book) ⓘ

Abu Hurairah (RAA) narrated that The Messenger of Allah said: "None of you should fast a day or two before the (beginning of the) mouth of Ramadan, unless it is a day on which one is in the habit of fasting (i.e. voluntary fasting that coincides with that day).” Agreed upon.

عَنْ أَبِي هُرَيْرَةَ ‏- رضى الله عنه ‏- قَالَ: قَالَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-{ لَا تَقَدَّمُوا رَمَضَانَ بِصَوْمِ يَوْمٍ وَلَا يَوْمَيْنِ, إِلَّا رَجُلٌ كَانَ يَصُومُ صَوْمًا, فَلْيَصُمْهُ } مُتَّفَقٌ عَلَيْهِ 1‏.‏ ‏1 ‏- صحيح.‏ رواه البخاري ( 1914 )‏، ومسلم ( 1082 )‏ واللفظ لمسلم.‏