Allah (swt) confirms what the Prophet (saws) promised his companions, that Allah (swt) will send down the angels by saying:

{بَلَى} {yes}. Hence, there are two conditions for winning the battle and for the descent of the angels, that are clarified in following:

إِن تَصْبِرُواْ وَتَتَّقُواْ {you remain patient and conscious of Allah}: He gave precedence to patience over piety, just as patience took precedence over prayer in other verses such as:

يَا أَيُّهَا الَّذِينَ آمَنُواْ اسْتَعِينُواْ بِالصَّبْرِ وَالصَّلاَةِ إِنَّ اللّهَ مَعَ الصَّابِرِينَ

{O you who have believed, seek help through patience and prayer. Indeed, Allah is with the patient.}  (Al-Baqara: 153)

Accordingly, fighting needs patience, same as science needs patience, developing needs patience, striving oneself requires patience, and going through life requires patience. Patience is the essential weapon of the believer, but patience is mixed with piety and is mixed with prayer, and prayer is a sign of piety.

Now, what are the weapons that we should use after we consider the combative weapons in addition to any other worldly tools? There are two weapons: patience and piety.