The Messenger of Allah ﷺ said, "The most burdensome prayers for the hypocrites are the night prayer and the dawn prayer..."
قال رسول الله ﷺ: إن أثقل صلاة على المنافقين صلاة العشاء وصلاة الفجر…
Bukhari narrated it in adhan (657), and Muslim in mosques (650:252), both from the hadith of Amash, who said, Abu Salih narrated to me, from Abu Hurairah, who said, then he mentioned it.