Once Allah's Messenger (ﷺ) got up for delivering the Khutba and I heard him after "Tashah-hud" saying "Amma ba'du."
Sahih al-Bukhari Book 11, Hadith 50
← Previous Hadith One night Allah's Messenger (ﷺ) (p.b.u.h) stood up after the prayer and recited "Tashah-hud" and then praised Allah as He deserved and said, "Amma ba'du."

Sahih al-Bukhari Book 11, Hadith 49 Next Hadith → Once the Prophet (ﷺ) ascended the pulpit and it was the last gathering in which he took part. He was covering his shoulder with a big cloak and binding his head with an oily bandage. He glorified and praised Allah and said, "O people! Come to me." So the people came and gathered around him and he then said, "Amma ba'du." "From now onward the Ansar will decrease and other people will increase. So anybody who becomes a ruler of the followers of Muhammad and has the power to harm or benefit people then he should accept the good from the benevolent amongst them (Ansar) and overlook the faults of their wrong-doers."

Sahih al-Bukhari Book 11, Hadith 51