It wasnarrated from Abu Hurairah that the Messenger of Allah (ﷺ)said:
"Whoever does not fast one day in Ramadan without having aconcession allowing that, fasting for a lifetime will not make up forthat." (FR)
English reference (FR): Vol. 1, Book 7, Hadith 1672 (FR)
Arabic reference (FR): Book 7, Hadith 1742 (FR)