Hadith #2335 (Sunan Abi Dawud)
Book: Fasting (Kitab Al-Siyam)
Narrator(s): Abu Salama bin 'Abdur Rahman أبو سلمة بن عبد الرحمن بن عوف, Ahmad bin Hanbal أحمد بن حنبل, Muhammad bin Ibrahim bin al-Harith محمد بن إبراهيم بن الحارث, Muhammad bin Ja'far bin Abi Kathir محمد بن جعفر بن أبي كثير, Shu'bah bin al-Hajjaj شعبة بن الحجاج, Tauba al-'Anbari al-Basri توبة العنبري البصري, Umm Salamah
Grade: Sahih

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.

Source: https://parallelquran.com/hadith/sunan-abi-dawud-2335/