Sayyiduna Abdullah bin Hanzalah (may Allah be pleased with him) narrates: A man greeted the Prophet (peace and blessings be upon him) with salam; the Prophet (peace and blessings be upon him) had urinated a short while before. The Prophet (peace and blessings be upon him) gave him no reply until he passed his hand over the wall, that is, he performed dry ablution (tayammum) (and then returned his greeting).
Imam Ahmad recorded it; its chain contains a narrator who is not named.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1504