Daniel 10:2

I Daniel was mourning three full weeks— Various causes are assigned for this mourning of the prophet. Usher thinks that it was on account of the interruption given by the Samaritans to the rebuilding of the temple. But I am persuaded, says Calmet, that it arose principally from the obscurity which the prophet found in the prophesies revealed to him; which indeed may be collected from the angel's touching upon no other cause of mourning. In consequence of Daniel's fasting, &c. he appears, and explains to him, in a clearer manner, what had been more obscurely revealed in the preceding visions.