I asked Abu Saeed Khudri about the lower garment, and he replied, "You have asked one who knows. The Messenger of Allah ﷺ said, 'The Muslim's lower garment should reach the middle of his shins, and there is no harm, or no blame, in it being anywhere between that and the ankles. Whatever falls below the ankles is in the Fire. Whoever drags his garment out of arrogance, Allah will not look at him.'"
حدثنا حفص بن عمر حدثنا شعبة
سألت أبا سعيد الخدري عن الإزار فقال على الخبير سقطت قال رسول الله ﷺ إزرة المسلم إلى نصف الساق ولا حرج أو لا جناح فيما بينه وبين الكعبين ما كان أسفل من الكعبين فهو في النار من جر إزاره بطرا لم ينظر الله إليه
Its isnad is sahih. Ibn Majah narrated it in the Book of Clothing, chapter "The Position of the Waist-Wrap, Where Is It?", hadith no. 3573, from the hadith of Ala bin Abdul-Rahman bin Yaqub, through him.