It wasnarrated that 'Abdullah bin 'Amr said:
"The Messenger of Allah(ﷺ) said: 'Do not be like so-and-so, who used to pray voluntarynight prayers then stopped praying voluntary night prayers." (RU)
English reference (RU): Vol. 1, Book 5, Hadith 1331 (RU)
Arabic reference (RU): Book 5, Hadith 1392 (RU)