Silsilat al-Ahadith al-Sahihah

It is narrated from Sayyiduna Anas (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "The lower edge of the izar (garment) should be up to the middle of the shin." But when he (peace and blessings be upon him) saw that this command was difficult for the Muslims, he said: "Up to the ankles is fine, but there is no good in letting it go below them."