It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "How can I be at ease when the one with the Horn has already put the Horn to his mouth?" And the Messenger of Allah (peace and blessings be upon him) bowed his forehead (and said): "He is waiting for when he will be commanded, so that he may blow." The Companions said: O Messenger of Allah, then what should we say? He (peace and blessings be upon him) said: "Allah is sufficient for us, and He is the best Disposer of affairs" [Al Imran: 173]. Then the Messenger of Allah (peace and blessings be upon him) recited this verse: "Then when the Trumpet is blown" [Al-Muddaththir: 8].
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12616