The Messenger of Allah ﷺ took hold of the muscle of my shin, or his own shin, and said, "This is the place where the lower garment should reach. If you insist on more, then a little lower. If you insist on more than that, then the lower garment has no right to reach the ankles."
حدثنا قتيبة حدثنا أبو الأحوص عن أبي إسحق عن مسلم بن نذير
أخذ رسول الله ﷺ بعضلة ساقي أو ساقه فقال هذا موضع الإزار فإن أبيت فأسفل فإن أبيت فلا حق للإزار في الكعبين
Its isnad is sahih. Ibn Majah also narrated it in "Clothing, the chapter on where the waist wrap should be worn," hadith 3572, from the hadith of Abu Ahwas, and Nasai narrated it, hadith 5331, from the hadith of Abu Ishaq, similarly.