Sahih al-Bukhari 340
Sahih al-Bukhari · Book 7: Rubbing hands and feet with dust (Tayammum) · Tayammum is for the hands and the face
Narrated `Abdur Rahman bin Abza:
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ ، قَالَ حَدَّثَنَا شُعْبَةُ ، عَنِ الْحَكَمِ ، عَنْ ذَرٍّ ، عَنِ ابْنِ عَبْدِ الرَّحْمَنِ بْنِ أَبْزَى ، عَنْ أَبِيهِ ، أَنَّهُ شَهِدَ عُمَرَ وَقَالَ لَهُ عَمَّارٌ كُنَّا فِي سَرِيَّةٍ فَأَجْنَبْنَا، وَقَالَ تَفَلَ فِيهِمَا.
that while he was in the company of `Umar, `Ammar said to `Umar, "We were in a detachment and became Junub and I blew the dust off my hands (performed the rolling over the earth and prayed.)"