Muwatta Malik 373

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ أَبِي جَعْفَرٍ الْقَارِئِ، أَنَّهُ قَالَ رَأَيْتُ عَبْدَ اللَّهِ بْنَ عُمَرَ إِذَا أَهْوَى لِيَسْجُدَ مَسَحَ الْحَصْبَاءَ لِمَوْضِعِ جَبْهَتِهِ مَسْحًا خَفِيفًا ‏.‏

Yahya related to me from Malik that Abu Jafar al-Qari said, "I saw Abdullah ibn Umar quickly brush away the small stones from the place where he was going to put his forehead as he was going down into sajda

Reference

Muwatta Malik 373

In-book

Book 9, Hadith 48