Riyad as-Salihin 1073
Abu Hurairah (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) said, "No Salat is more burdensome to the hypocrites than the Fajr (dawn) prayer and the 'Isha' (night) prayer; and if they knew their merits, they would come to them even if they had to crawl to do so." [Al-Bukhari and Muslim] .
وعنه قال‏:‏ قال رسول الله صلى الله عليه وسلم ‏:‏ ‏
"‏ليس صلاة أثقل على المنافقين من صلاة الفجر والعشاء ولو يعلمون ما فيهما  لأتوهما ولو حبوًا‏"‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏‏.‏