It is narrated from Muhammad bin Ibrahim that Sayyidah Aishah (may Allah be pleased with her) said: 'Subhan Allah' (Glory be to Allah)! Are the dead of the believers impure? It is just like a man who took hold of a piece of wood and carried it (that is, the dead are not impure).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1472