Sayyiduna Anas bin Malik (may Allah be pleased with him) said that the Prophet (peace and blessings be upon him) took off his sandals during the prayer only once, and the people also took off their sandals. The Prophet (peace and blessings be upon him) said: "Why did you take off your sandals?" They said: "We saw that you took them off, so we took them off too." He (peace and blessings be upon him) said: "Jibril (peace be upon him) informed me that there was filth on both of them."
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated these two hadiths from Thumamah except Abdullah bin al-Muthanna al-Ansari."
Hadith Referenceالمعجم الأوسط / باب العين / 4293
Hadith Gradingمحدثین:رجاله رجال الصحيح
Hadith Takhrij«قال الهيثمي: رجاله رجال الصحيح «مجمع الزوائد ومنبع الفوائد، ج 2، ص 56»» «أخرجه الضياء المقدسي فى «الأحاديث المختارة» برقم: 1831، والحاكم فى «المستدرك» برقم: 487، والبيهقي فى «السنن الكبرى» برقم: 4158»