Sayyiduna Abu Ayyash Zarqi (may Allah be pleased with him) says: We were with the Messenger of Allah (peace and blessings be upon him) at the place of Usfan, when the polytheists confronted us. Their leader was Khalid bin Walid. They were between us and the Qiblah. The Messenger of Allah (peace and blessings be upon him) led us in the Zuhr prayer. They said among themselves: These Muslims are engaged in prayer; if only we could take advantage of their heedlessness. Then they said: Soon, another time for their prayer will come, which is dearer to them than their lives and children. At that very moment, between Zuhr and Asr, Jibreel (peace be upon him) descended with these verses: {وَاِذَا کُنْتَ فِیْہِمْ فَأَقَمْتَ لَہُمْ الصَّلَاۃَ … } (When you are among them, and lead them in prayer ...). When the time for Asr came, the Messenger of Allah (peace and blessings be upon him) ordered the companions to stand with their weapons. We formed two rows behind him. When he (peace and blessings be upon him) bowed in ruku', we all bowed, and when he rose from ruku', we also rose. When he (peace and blessings be upon him) went into prostration (sajdah), only those in the first row behind him performed sajdah, while those in the second row stood and kept watch. When those who had performed sajdah stood up, the second row sat in their places and performed sajdah. Then (at the beginning of the second rak'ah), the front row moved to the back and the back row came forward. Then, in the same way, all the worshippers performed ruku' with the Prophet (peace and blessings be upon him) and rose from ruku'. Then, when he went into sajdah, the first row performed sajdah with him, and the second row stood and kept watch. When he and the first row sat after sajdah, the second row sat and performed sajdah (and all sat for tashahhud, then) all together said salam and completed the prayer. The Messenger of Allah (peace and blessings be upon him) led the prayer in this manner twice: once at Usfan and once in the region of Banu Sulaym.