السلام
كلمة (السلام) في اللغة مصدر من الفعل (سَلِمَ يَسْلَمُ) وهي...
Jābir ibn ‘Abdullāh al-Ansāri (may Allah be pleased with him) reported: I witnessed the prayer of fear with the Messenger of Allah (may Allah's peace and blessings be upon him). We stood in two rows behind the Messenger of Allah (may Allah's peace and blessings be upon him) and the enemy was between us and the Qiblah. The Prophet (may Allah's peace and blessings be upon him) said Takbīr and we all did. He then bowed and we all bowed. He then raised his head from bowing, and we all did. He then prostrated with the row behind him, while the back row stood in the face of the enemy. When the Prophet (may Allah's peace and blessings be upon him) completed the prostration and the row behind him stood, the back row prostrated and then stood up. Then the back row moved to the front and the front row moved to the back. Then the Prophet (may Allah's peace and blessings be upon him) bowed and we all bowed. He then raised his head from bowing and we also raised ours. Then he and the row behind him, which was back in the first Rak‘ah, prostrated, whereas the back row stood in the face of the enemy. When the Prophet (may Allah's peace and blessings be upon him) and the row behind him finished the prostration, the back row prostrated. Then the Prophet (may Allah's peace and blessings be upon him) ended the prayer with Taslīm and we all did the same. Jābir said: ''As those guards of yours do with their chiefs.'' Al-Bukhāri mentioned part of it: ''That he performed the prayer of fear with the Prophet (may Allah's peace and blessings be upon him) in the seventh battle, i.e. the battle of Dhāt Ar-Riqā‘."
شرح الحديث :
This Hadīth describes a form of the prayer of fear, i.e. when the enemy is in the direction of the Qiblah. The Prophet (may Allah's peace and blessings be upon him) divided the army into two groups: one in the front row and another in the back row. Then he lead them in the prayer, starting with Takbīr, then all recited, bowed, and rose from bowing. Then the Prophet (may Allah's peace and blessings be upon him) and the row behind him, prostrated. Rising for the second Rak‘ah, the back row which was guarding them from the enemy, prostrated. When they rose, the front row went back and the back row stepped forward, so that both rows were even in what they had performed, and the first row did not stand in its place for the entire prayer. What was done in the first Rak‘ah was repeated in the second Rak‘ah. All made Tashahhud and ended the prayer following the Prophet (may Allah's peace and blessings be upon him). This way of performing the prayer of fear was suitable for the state of the Prophet (may Allah's peace and blessings be upon him) and his Companions at that time. They were able to see their enemy, who was in the direction of Qiblah, while standing and bowing in prayer. Also, in this position, they were safe from a rear attack.