The following is the purport from the 10th Canto of the Srimad Bhagavatam.
The spiritual master is sometimes glorified as sarva-devamayo guruh (SB 11.17.27). By the grace of the guru, the spiritual master, one can understand the different kinds of devas. The word deva refers to God, the Supreme Personality of Godhead, who is the original source of all the demigods, who are also called devas. In Bhagavad-gita (10.2) the Lord says, aham adir hi devanam: "I am the source of all the devas." The Supreme Lord, Visnu, the Original person, expands in different forms. Tad aiksata bahu syam (Chandogya Upanisad 6.2.3). He alone has expanded into many. Advaitam acyutam anadim ananta-rupam (Bs. 5.33). There are different grades of forms, known as svamsa and vibhinnamsa. The svamsa expansions, or visnu-tattva, are the Supreme Personality of Godhead, whereas the vibhinnamsa are jiva-tattva, who are part and parcel of the Lord (mamaivamso jiva-loke jiva-bhutah sanatanah [Bg. 15.7]). If we accept Krsna as the Supreme Personality of Godhead and worship Him, all the parts and expansions of the Lord are automatically worshiped. Sarvarhanam acyutejya (SB 4.31.14). Krsna is known as Acyuta (senayor ubhayor madhye ratham sthapaya me 'cyuta [Bg. 1.21]). By worshiping Acyuta, Krsna, one automatically worships all the demigods. There is no need of separately worshiping either the visnu-tattva or jiva-tattva. If one concentrates upon Krsna, one worships everyone.
SB 10.1.56 purport