Riyad us Saliheen: Hadith 1062

Once the Messenger of Allah (ﷺ) delayed the night prayer ('Isha') till midnight. He (ﷺ) turned to us after Salat (prayer) and said, "The people slept after performing their Salat, but you who waited, will be accounted as engaged in Salat throughout the period of your waiting."

[Al-Bukhari].