مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 407
Purification
How to Perform Ablution - Section 2
وَعَن الْمُسْتَوْرد بن شَدَّاد قَالَ: رَأَيْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِذَا تَوَضَّأَ يُدَلِّكُ أَصَابِعَ رِجْلَيْهِ بِخِنْصَرِهِ. رَوَاهُ التِّرْمِذِيّ وَأَبُو دَاوُد وَابْن مَاجَه
Al-Mustaurid b. Shaddad said that he saw God’s messenger rubbing his toes with his little finger when he performed ablution. Tirmidhi, Abu Dawud and Ibn Majah transmitted it.
Mishkat al-Masabih, 407صَحِيح (الألباني)