SB 3.10.5 P Divisions of the Creation
The material world is called illusory because it is a place of forgetfulness of the transcendental service of the Lord. Thus one engaged in the the Lord's devotional service in the material world may sometimes be very much disturbed by awkward circumstances. There is a declaration of war between the two parties, the illusory energy and the devotee, and sometimes the weak devotees fall victim to the onslaught of the powerful illusory energy. Lord Brahma, however, was sufficiently strong, by the causeless mercy of the Lord, and he could not be victimized by the material energy, although it gave him cause for anxiety when it managed to totter the existence of his position.