The Messenger of Allah ﷺ said, "Whoever fasts perpetually has neither fasted nor broken his fast, he has neither fasted nor broken his fast."
حدثنا يزيد بن هارون قال أخبرنا شعبة عن قتادة
قال رسول الله ﷺ من صام الدهر لا صام ولا أفطر وما صام ولا أفطر
Its isnad is sahih. Mentioned previously at 16256.