Not graded
Riyad as-Salihin 1176
Narrator:Jābir ibn ‘Abdullāh
وعن جابر رضي الله عنه قال: سئل رسول الله صلى الله عليه وسلم : أي الصلاة أفضل؟ قال:
"طول القنوت"
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].
Cited in Riyad as-Salihin (No. 1176).