الآية رقم (102) - وَإِذَا كُنتَ فِيهِمْ فَأَقَمْتَ لَهُمُ الصَّلاَةَ فَلْتَقُمْ طَآئِفَةٌ مِّنْهُم مَّعَكَ وَلْيَأْخُذُواْ أَسْلِحَتَهُمْ فَإِذَا سَجَدُواْ فَلْيَكُونُواْ مِن وَرَآئِكُمْ وَلْتَأْتِ طَآئِفَةٌ أُخْرَى لَمْ يُصَلُّواْ فَلْيُصَلُّواْ مَعَكَ وَلْيَأْخُذُواْ حِذْرَهُمْ وَأَسْلِحَتَهُمْ وَدَّ الَّذِينَ كَفَرُواْ لَوْ تَغْفُلُونَ عَنْ أَسْلِحَتِكُمْ وَأَمْتِعَتِكُمْ فَيَمِيلُونَ عَلَيْكُم مَّيْلَةً وَاحِدَةً وَلاَ جُنَاحَ عَلَيْكُمْ إِن كَانَ بِكُمْ أَذًى مِّن مَّطَرٍ أَوْ كُنتُم مَّرْضَى أَن تَضَعُواْ أَسْلِحَتَكُمْ وَخُذُواْ حِذْرَكُمْ إِنَّ اللّهَ أَعَدَّ لِلْكَافِرِينَ عَذَابًا مُّهِينًا

(102) - { And when you are among them and lead them in prayer, let a group of them stand [in prayer] with you and let them carry their arms. And when they have prostrated, let them be [in position] behind you and have the other group come forward which has not [yet] prayed and let them pray with you, taking precaution and carrying their arms. Those who disbelieve wish that you would neglect your weapons and your baggage so they could come down upon you in one [single] attack. But there is no blame upon you, if you are troubled by rain or are ill, for putting down your arms, but take precaution. Indeed, Allah has prepared for the disbelievers a humiliating punishment.}

The Fear prayer has different forms; it is performed as follows:

The Prophet (saws) stands as Imam, the first group pray with him, whereas the second group watching the enemy to protect the prayers from any sudden attach, then when the first Rek’a completed, this second group comes and stands to pray the second Rek’a. In this case bother of the groups would have prayed behind the Prophet (saws). But the question is why do they hold their arms while they are in Allhs’s protection and the Prophet (saws) was with their Imam and Allah (swt) says:

 إِن يَنصُرْكُمُ اللَّهُ فَلَا غَالِبَ لَكُمْ

(If Allah should aid you, no one can overcome you;) (Ali-Imran: 160)

The answer is: Allah (swt) had established ways in the universe and put means in this life, and connect the means with the results, so that if you do not take the required means you do not have to right to say this is my destiny. For example, if there is a car moving with high speed and a man threw himself in its way and consequently, he passes away, in this case it is true that he died because of what he has done but it is his destiny to die at that moment. In other words, Allah’s (swt) put reasons and orders the humans to follow the means and the evidence is the Fear prayer; despite the presence of the Messenger (saws) with them, Allah (swt) commanded them to take their weapons and take precaution so that He (swt) teaches people not to abandon the causes that He (swt) has created and to abide by them.