From Imam Reza's (peace be upon him) point of view, the very useful and beneficial weapon in the battlefield with both external and internal enemies is to pay a very special attention to prayer.
Imam Reza (peace be upon him) always used to say to his companions: try to use the weapon of the divine prophets, he was asked about what the weapon of the divine prophet was, he used to say: prayer.
source : erfan.ir
