الشمائل المحمدية

Abu Huraira said (may Allah be well pleased with him): "Allah’s Messenger (Allah bless him and give him peace) used to perform the ritual prayer until his feet had begun to swell, so he was asked: 'Must you do this, when it has come to you that Allah has already forgiven you your former and your latter sins?’ He replied: 'Shall I not be a thankful servant?'”