Hadith: I passed by the Messenger of Allah (may Allah's peace and blessings be upon him) and my lower garment was trailing. Therefore, he said: O ‘Abdullāh, pull up your lower garment. I raised it and he said: Up! So I raised it further, and I have been doing so since then. Some people said: Up to where? He said: To the middle of the shins

عن ابنِ عمرَ رضي الله عنهما ، قال: مَرَرْتُ على رسولِ اللهِ صلى الله عليه وسلم وفي إِزَارِي اسْتِرْخَاءٌ، فقال: «يا عبدَ اللهِ، ارْفَعْ إِزَارَكَ» فَرَفَعْتُهُ ثم قال: «زِدْ» فَزِدْتُ، فما زِلْتُ أَتَحَرَّاهَا بَعْدُ، فقال بعضُ القَوْمِ: إلى أين؟ فقال: إلى أَنْصَافِ السَّاقَيْنِ.
[صحيح] - [رواه مسلم]

Ibn ‘Umar (may Allah be pleased with him) reported: I passed by the Messenger of Allah (may Allah's peace and blessings be upon him) and my lower garment was trailing. Therefore, he said: "O ‘Abdullāh, pull up your lower garment." I raised it and he said: 'Up!’ So I raised it further, and I have been doing so since then. Some people said: "Up to where?" He said: "To the middle of the shins."
Sahih/Authentic. - [Muslim]

Explanation

Ibn ‘Umar (may Allah be pleased with him) reported that he passed by the Messenger of Allah (may Allah's peace and blessings be upon him) and his lower garment was trailing. So the Prophet told him to pull it up. ‘Abdullāh raised it up to the ankles or close to them. The Prophet (may Allah's peace and blessings be upon him) further asked him to pull it up, for doing so was better for a cleaner outfit. ‘Abdullāh pulled it up to the middle of his shins. He kept doing so since then out of his care for and adherence to the Sunnah. Some people asked him up to where the Prophet (may Allah's peace and blessings be upon him) eventually asked him to raise his lower garment. He said up to the middle of the shins.