Sunan Abu Dawud
171
Sahih+3

Abu Asad b. ‘Amr said:I asked Anas b. Malik about ablution. He replied: The Prophet (ﷺ) performed ablution for each prayer and we offered (many) prayers with the same ablution

SahihAl-Albani
SahihMuhammad Muhyi Al-Din Abdul Hamid