Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) said: On the day of the Trench, we were prevented (from prayer) until a part of the night had passed, then the fighting ceased, as Allah the Exalted said: «وَكَفَىاللَّهُالْمُؤْمِنِينَالْقِتَالَوَكَانَاللَّهُقَوِيًّاعَزِيزًا»[احزاب 25/33] . So the Noble Prophet (peace and blessings be upon him) called Sayyiduna Bilal (may Allah be pleased with him) and ordered him to give the iqamah (call to prayer), and he performed the Zuhr prayer in a very good manner, just as he used to perform it at its time. Then the Prophet (peace and blessings be upon him) told Sayyiduna Bilal (may Allah be pleased with him) to give the iqamah and he performed the Asr prayer. Then he ordered Sayyiduna Bilal (may Allah be pleased with him), he gave the iqamah and the Prophet (peace and blessings be upon him) performed the Maghrib prayer. Then he ordered Sayyiduna Bilal (may Allah be pleased with him), he gave the iqamah and the Prophet (peace and blessings be upon him) performed the Isha prayer. And this was before the verse of Salat al-Khawf «فَإِنْخِفْتُمْفَرِجَالًاأَوْرُكْبَانًا ...»[بقرة: 239/2] was revealed.
Hadith Referenceسنن دارمي / من كتاب الصللاة / 1563
In this hadith, the mention is of performing four prayers together, whereas in the Sahihayn only ‘Asr and Maghrib are mentioned. In any case, this is the ruling from before the legislation of Salat al-Khawf (the prayer of fear), as is stated in the hadith.