The Messenger of Allah ﷺ said, "When you hear the call to prayer, repeat what the muezzin says."
أن رسول الله ﷺ قال: إذا سمعتم النداء فقولوا مثل ما يقول المؤذن.
Malik narrated it in "Prayer" (2) from Ibn Shihab, from Ata bin Yazid Laythi, from Abu Saeed Khudri, and he mentioned it. Bukhari narrated it in "Adhan" (611), and Muslim in "Prayer" (383), both of them by way of Malik.