Hadithcore
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." <b>[Muslim]</b>.

وعن جابر رضي الله عنه قال‏:‏ سئل رسول الله صلى الله عليه وسلم ‏:‏ أي الصلاة أفضل‏؟‏ قال‏:‏ ‏

‏طول القنوت‏

‏ ‏(‏‏(‏رواه مسلم‏)‏‏)‏‏.‏

References1 variant
In-Book Reference
Book 8, Hadith 186
Sharh · explanationclick to expand
<b>Guidance from the Hadith:</b><br> 1) Long standing is one of the best acts in prayer, for those who are able to do it.<br> 2) It is preferable to offer the prayer in a proportionate manner. In other words, if we prolong the standing, we should also prolong other pillars of the prayer.