Seeing the situation that had been created by the will of the Supreme, the unlimitedly powerful Lord, whose determination is infallible, took the wonderful shape of a tortoise, entered the water, and lifted the great Mandara Mountain.Śrīmad-Bhāgavatam 8.7.8
vilokya vighneśa-vidhiṁ tadeśvaro
kṛtvā vapuḥ kacchapam adbhutam mahat
praviśya toyaṁ girim ujjahāra
vilokya — observing; vighna — the obstruction (the sinking of the mountain); īśa-vidhim — by the providential arrangement; tadā — then; īśvaraḥ — the Supreme Personality of Godhead; duranta-vīryaḥ — inconceivably powerful; avitatha — infallible; abhisandhiḥ — whose determination; kṛtvā — expanding; vapuḥ — body; kacchapam — tortoise; adbhutam — wonderful; mahat — very great; praviśya — entering; toyam — the water; girim — the mountain (Mandara); ujjahāra — lifted.
Here is evidence that the Supreme Personality of Godhead is the supreme controller of everything. As we have previously described, there are two classes of men — the demons and the demigods — but neither of them are supremely powerful. Everyone has experienced that hindrances are imposed upon us by the supreme power. The demons regard these hindrances as mere accidents or chance, but devotees accept them to be acts of the supreme ruler. When faced with hindrances, therefore, devotees pray to the Lord. Tat te ’nukampāṁ susamīkṣamāṇo bhuñjāna evātma-kṛtaṁ vipākam. Devotees endure hindrances, accepting them to be caused by the Supreme Personality of Godhead and regarding them as benedictions. Demons, however, being unable to understand the supreme controller, regard such hindrances as accidental. Here, of course, the Supreme Personality of Godhead was present personally. It was by His will that there were hindrances, and by His will those hindrances were removed. The Lord appeared as a tortoise to support the great mountain. Kṣitir iha vipulatare tava tiṣṭhati pṛṣṭhe. The Lord held the great mountain on His back. Keśava dhṛta-kūrma-śarīra jaya jagadīśa hare. Dangers can be created by the Supreme Personality of Godhead, and they can also be removed by Him. This is known to devotees, but demons cannot understand it.