´It was narrated from Salim, from his father, that:` The Messenger of Allah [SAW] said: "Whoever drags his garment out of pride, Allah will not look at him on the Day of Resurrection." Abu Bakr said: "O Messenger of Allah, one side of my Izar slips unless I pay attention to it." The Prophet [SAW]: "You are not one of those who do that out of pride."
Hadith Referenceسنن نسائي / كتاب الزاينة (من المجتبى) / 5337
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:صحيح بخاري
It is understood that the aforementioned punishment for letting the lower garment hang below the ankles is for the arrogant person or for one who has made it a habit. If, however, someone’s lower garment occasionally hangs down unintentionally or out of negligence, and upon realizing it he raises it up, then he is excused. And Allah knows best.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 5337