Sahih Bukhari Volume 2, Book 25, Hadith 1660

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ مُحَمَّدِ بْنِ أَبِي بَكْرٍ الثَّقَفِيِّ، أَنَّهُ سَأَلَ أَنَسَ بْنَ مَالِكٍ وَهُمَا غَادِيَانِ مِنْ مِنًى إِلَى عَرَفَةَ كَيْفَ كُنْتُمْ تَصْنَعُونَ فِي هَذَا الْيَوْمِ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ كَانَ يُهِلُّ مِنَّا الْمُهِلُّ فَلاَ يُنْكِرُ عَلَيْهِ، وَيُكَبِّرُ مِنَّا الْمُكَبِّرُ فَلاَ يُنْكِرُ عَلَيْهِ‏

Narrated By Muhammad bin Abu Bakr Al-Thaqafi : I asked Anas bin Malik while we were proceeding from Mina to 'Arafat, "What do you use to do on this day when you were with Allah's Apostle ?" Anas said, "Some of us used to recite Talbiya and nobody objected to that, and others used to recite Takbir and nobody objected to that."