Srimad Bhagavatam Canto 03, Chapter 05, Text 43

SB 3.5.43

visvasya janma-sthiti-samyamarthe
 krtavatarasya padambujam te
vrajema sarve saranam yad isa
 smrtam prayacchaty abhayam sva-pumsam
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
O Lord, You assume incarnations for the creation, maintenance and dissolution of the cosmic manifestation, and therefore we all take shelter of Your lotus feet because they always award remembrance and courage to Your devotees.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
For the creation, maintenance and dissolution of the cosmic manifestations there are three incarnations: Brahma, Visnu and Mahesvara (Lord Siva). They are the controllers or masters of the three modes of material nature, which cause the phenomenal manifestation. Visnu is the master of the mode of goodness, Brahma is the master of the mode of passion, and Mahesvara is the master of the mode of ignorance. There are different kinds of devotees according to the modes of nature. Persons in the mode of goodness worship Lord Visnu, those in the mode of passion worship Lord Brahma, and those in the mode of ignorance worship Lord Siva. All three of these deities are incarnations of the Supreme Lord Krsna because He is the original Supreme Personality of Godhead. The demigods directly refer to the lotus feet of the Supreme Lord and not to the different incarnations. The incarnation of Visnu in the material world is, however, directly worshiped by the demigods. It is learned from various scriptures that the demigods approach Lord Visnu in the Ocean of Milk and submit their grievances whenever there is some difficulty in the administration of universal affairs. Although they are incarnations of the Lord, Lord Brahma and Lord Siva worship Lord Visnu, and thus they are also counted amongst the demigods and not as the Supreme Personality of Godhead. Persons who worship Lord Visnu are called demigods, and persons who do not do so are called asuras, or demons. Visnu always takes the part of the demigods, but Brahma and Siva sometimes take the side of the demons; it is not that they become one in interest with them, but sometimes they do something in order to gain control over the demons.
Srimad Bhagavatam Canto 03, Chapter 05, Text 42
Srimad Bhagavatam Canto 03, Chapter 05, Text 44