Muhammad bin Ja'far bin Abi Kathir محمد بن جعفر بن أبي كثير · Fasting (Kitab Al-Siyam)

The Messenger of Allah (ﷺ) as saying: Do not fast one day or two days just before Ramadan, except in the case of a man who has been in the habit of observing the particular fast, for he may fast on that day.