جامع الترمذي

Narrated Abu Sa'eed Al-Khudri: that the Messenger of Allah (ﷺ) said: "How can I be comfortable when the one with the horn is holding it in his lips and his forehead is leaning forward, waiting to be given permission to blow?" The Muslims said: "So what should we say, O Messenger of Allah?" He said: "Say: 'Allah is sufficient for us and what a good protector He is. We rely upon [our Lord] Allah'" - and perhaps Sufyan (one of the narrators) said: "upon Allah we rely."