What is Brahmamuhurta? Why is it eulogized by the Rishis?

4 a.m. in the morning is termed as Brahmamuhurta. Because it is favourable for meditation on God or Brahman, it is called Brahmamuhurta. At this particular hour, the mind is very calm and serene. It is free from worldly thoughts, worries and anxieties. The mind is like a blank sheet of paper and comparatively free from worldly Samskaras. It can be very easily moulded at this time before worldly distractions enter the mind. Further, the atmosphere also is charged with more Sattva at this particular time. There is no bustle and noise outside.

Swami Sivananda