The Messenger of Allah ﷺ said, "None of you should precede the month by fasting one or two days ahead, except for someone who was already in the habit of observing a regular fast, in which case he may fast it."
أخبرني عمران بن يزيد بن خالد قال حدثنا محمد بن شعيب قال أنبأنا الأوزاعي عن يحيى قال حدثني أبو سلمة قال
أن رسول الله ﷺ قال لا يتقدمن أحد الشهر بيوم ولا يومين إلا أحد كان يصوم صياما قبله فليصمه
[Sahih] See the previous hadith, which is in Kubra, no. 2483. It was also narrated by Ibn Majah, no. 1650, from the hadith of Uzai, through the same chain.