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).
Sahih al-Bukhari Book 10, Hadith 137
← Previous Hadith The Prophet (ﷺ) said, "Perform the bowing and the prostrations properly. By Allah, I see you from behind me (or from behind my back) when you bow or prostrate."

Sahih al-Bukhari Book 10, Hadith 136 Next Hadith → Allah's Messenger (ﷺ) used to keep silent between the Takbir and the recitation of Qur'an and that interval of silence used to be a short one. I said to the Prophet (ﷺ) "May my parents be sacrificed for you! What do you say in the pause between Takbir and recitation?" The Prophet (ﷺ) said, "I say, 'Allahumma, baa`id baini wa baina khatayaya kama baa`adta baina l-mashriqi wa l-maghrib. Allahumma, naqqini min khatayaya kama yunaqqa th-thawbu l-abyadu mina d-danas. Allahumma, ighsil khatayaya bi l-maa'i wa th-thalji wa l-barad (O Allah! Set me apart from my sins (faults) as the East and West are set apart from each other and clean me from sins as a white garment is cleaned of dirt (after thorough washing). O Allah! Wash off my sins with water, snow and hail.)"

Sahih al-Bukhari Book 10, Hadith 138