Ibn ‘Umar said that God’s Messenger prayed two rak'as in Mina, as did Abu Bakr after his death, ‘Umar after Abu Bakr’s death, and ‘Uthman in the early part of his Caliphate, but afterwards ‘Uthman prayed four. When Ibn ‘Umar prayed with an imam he prayed four, but when he prayed alone he prayed two. (Bukhari and Muslim.)
Hadith Referenceمشكوة المصابيح / كتاب الصلاة / 1347
Hadith Gradingالألبانی:مُتَّفق عَلَيْهِ | زبیر علی زئی:متفق عليه
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «متفق عليه، رواه البخاري (1082) و مسلم (694/16)»