Hadith 3:103
‘Abdallah b. Zaid said that the Prophet performed each detail of his ablution twice. Bukhari transmitted it.
وَعَنْ عَبْدِ اللَّهِ بْنِ زَيْدٍ: أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ تَوَضَّأَ مَرَّتَيْنِ مَرَّتَيْنِ. رَوَاهُ البُخَارِيّ
Original Reference: Mishkat al-Masabih 396