إِذَا سَمِعْتُمْ صِيَاحَ الدِّيَكَةِ فَاسْأَلُوا اللَّهَ مِنْ فَضْلِهِ؛ فَإِنَّهَا رَأَتْ مَلَكاً وَإِذَا سَمِعْتُمْ نَهِيقَ الْحِمَارِ فَتَعَوَّذُوا بِاللَّهِ مِنَ الشَّيطَانِ؛ فَإِنَّهُ رَأَى شَيْطَاناً
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When you hear the cock's crow, ask Allah for His favor upon you for surely it has seen an angel. When you hear the bray of a donkey, seek refuge in Allah from Satan, for surely it has seen a devil.
Al-Bukhari, cf. Al-Asqalani, Fathul-Bari 6/350, Muslim 4/2092.