Riyad as-Salihin 409
Abu Sa'id Al-Khudri (May Allah be pleased with him) reported:
Messenger of Allah (ﷺ) said, "How can I feel at ease when the Angel of the Trumpet, (Israfil) has put his lips to the Trumpet and is waiting for the order to blow it". He (ﷺ) perceived as if this had shocked his Companions, so he (ﷺ) told them to seek comfort through reciting: 'Hasbunallah wa ni'mal-Wakil [Allah (Alone) is Sufficient for us, and He is the Best Disposer of affairs (for us)] ". [At-Tirmidhi, who classified it as Hadith Hasan] .
وعن أبي سعدي الخدرى، رضي الله عنه، قال‏:‏ قال رسول الله، صلى الله عليه وسلم ‏"‏كيف أنعم وصاحب القرن قد التقم ، واستمع الإذن متى يؤمر بالنفخ فينفخ‏"‏ فكأن ذلك ثقل على أصحاب رسول الله ، صلى الله عليه وسلم فقال لهم‏:‏‏"‏قولوا ‏:‏حسبنا الله ونعم الوكيل‏"‏ ‏(‏‏(‏رواه الترمذي وقال حديث حسن‏)‏‏)‏‏.‏