Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 5
तद्विलोक्याब्जसम्भूतो वायुना यदधिष्ठित: ।पद्ममम्भश्च तत्कालकृतवीर्येण कम्पितम् ॥ ५ ॥
tad vilokyābja-sambhūtovāyunā yad-adhiṣṭhitaḥpadmam ambhaś ca tat-kāla-kṛta-vīryeṇa kampitam
Thereafter Brahmā saw that both the lotus on which he was situated and the water on which the lotus was growing were trembling due to a strong, violent wind.
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 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 Brahmā, 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.