(21) باب مَا يَقُوُلُ الإِمَامُ إِذَا رَفَعَ رَأْسَهُ مِنَ الرُّكُوعِ
It was narrated that Abu Hurairah said:
"When the Prophet (ﷺ) raised his head from bowing, he said: 'Allahumma Rabbana wa lakal-hamd (O Allah, our Lord and to You be the praise).'"
Reference: Sunan an-Nasa'i 1060
In-book reference: Book 12, Hadith 32
English translation: Vol. 2, Book 12, Hadith 1061