Riyad as-Salihin 1176
Jabir (May Allah be pleased with him) reported:
The Messenger of Allah (ﷺ) was asked: "Which Salat is the best?" He replied, " The best Salat is that in which Qiyam (the duration of standing) is longer." [Muslim] .
وعن جابر رضي الله عنه قال‏:‏ سئل رسول الله صلى الله عليه وسلم ‏:‏ أي الصلاة أفضل‏؟‏ قال‏:‏ ‏
"‏طول القنوت‏"‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏