(89) باب مَا يَقُولُ بَعْدَ التَّكْبِيرِ
Narrated Anas bin Malik:
The Prophet, Abu Bakr and `Umar used to start the prayer with "Al hamdu li l-lahi Rabbi l-`alamin (All praise is but to Allah, Lord of the Worlds).
Reference: Sahih al-Bukhari 743
In-book reference: Book 10, Hadith 137
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 1, Book 12, Hadith 710