The Messenger of Allah ﷺ said, "None of you should say, 'I have fasted the whole of Ramadan and stood in prayer through all of its nights.'"I do not know whether he disliked self-praise, or whether he meant that one must inevitably have some sleep or rest.
حدثنا مسدد حدثنا يحيى عن المهلب بن أبي حبيبة حدثنا الحسن
قال رسول الله ﷺ لا يقولن أحدكم إني صمت رمضان كله وقمته كله فلا أدري أكره التزكية أو قال لا بد من نومة أو رقدة
[Its chain of transmission is daif] Nasai narrated it in the chapter on Fasting, in the section on the permission to refer to the month of Ramadan simply as "Ramadan," no. 2111, from the hadith of Yahya Qattan through this route, and Ibn Hibban graded it sahih, no. 915. * Hasan Basri narrated with "an" (indicating a possible gap in the chain).