ब्रह्म मुहूर्त में सुबह ४ से ६ बजे के बीच या सूर्यास्त के समय। To avoid the sages from attaining moksha, the asuras accustomed to disturb them and often attacked them though deep in meditation. The sages prayed to Shiva for enable. This Hanuman Mantra is an extremely mystery https://www.youtube.com/watch?v=1G1uzSVseNU