Abu Hurairah and 'Aishah (May Allah be pleased with them) said:
The Prophet (ﷺ) prohibited observing continuous voluntary fasts beyond one day.[Al-Bukhari and Muslim]. (JA)
App reference (JA): Book 18, Hadith 254 (JA)
Arabic/English book reference (JA): Book 18, Hadith 1764 (JA)