وعن ابن عمر رضى الله عنهما
قال: مررت على رسول الله صلى الله عليه وسلم وفى إزاري استرخاء، فقال: «يا عبد الله، ارفع إزارك«فرفعت ثم قال: «زد»، فزدت، فما زلت أتحراها بعد. فقال بعض القوم: إلى أين؟ فقال: إلى أنصاف الساقين»
My lower garment was trailing as I passed by the Messenger of Allah (sallallahu alayhi wa sallam) so he said, “Raise your lower garment, Abdullah.” I lifted it up and he told me to raise it higher. I complied with his orders and as I was still trying to find the best place (for it), one of the people asked where it should reach and he (sallallahu alayhi wa sallam) replied, “Half way down the knees.”.
Riyad as-Salihin 799, Book 4, The Book of Dress, Hadith 22. 1 min read