Majma al-Zawaid — Hadith 4343

Sayyiduna Abdullah bin al-Zubayr (may Allah be pleased with them both) reports this saying of the Prophet (peace and blessings be upon him): "Any owner of camels who does not pay their due (that is, zakah) in their hardship and their ease (that is, whether they are fat and healthy or weak, in every case), when he comes on the Day of Resurrection, he will be laid flat before those camels on a barren plain, and they (the camels) will trample him with their feet. Whenever the first of them has passed, the last will start over again. This will go on until judgment is passed between the people; after that the person will see his way."
Al-Bazzar recorded it, and its narrators are thiqat (trustworthy).