Matthew Poole and continuators on Daniel 10:2

2 In those dayes I Daniel was mourning three full weeks .

There are several cause of Daniels mourning. 1. Because the Iews had Liberty to go out of Captivity, yet many of them staid still in Babylon. 2 Because when they were Building the Temple, Walls and City they were greatly hindred and molested, Ezra 4.4. 3. Because he foresaw the many calamities of the Iews that would befall them for their sins, especially in destroying the Messiah, and rejecting his Gospel.

He fasted and mourned all that time, both to declare his deep sense of those calamities ensuing, and to be in a better posture to receive Divine impressions, which usually God reveals to humble Souls.

Marginal references: Heb. weeks of days.