Imam Bukhari narrates: Abdullah bin Yusuf narrated to us, he said: Imam Malik informed us from Ibn Shihab from Ata bin Yazid al-Laithi from Abu Sa'id al-Khudri, may Allāh be pleased with him, he relates that the Messenger of Allāh ﷺ said:

When you hear the Adhan, then say the like of what the mu'adhdhin says.