Srimad Bhagavatam Canto 10, Chapter 08, Text 13

SB 10.8.13

asan varnas trayo hy asya
grhnato ’nuyugam tanuh
suklo raktas tatha pita
idanim krsnatam gatah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Your son Krsna appears as an incarnation in every millennium. In the past, He assumed three different colors — white, red and yellow and now He has appeared in a blackish color. [In another Dvapara-yuga, He appeared (as Lord Ramacandra) in the color of suka, a parrot. All such incarnations have now assembled in Krsna.]
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Partially explaining the position of Lord Krsna and partially covering the facts, Garga Muni indicated, “Your son is a great personality, and He can change the color of His body in different ages.” The word grhnatah indicates that Krsna is free to make His choice. In other words, He is the Supreme Personality of Godhead and may therefore do whatever He desires. In Vedic literature the different colors assumed by the Personality of Godhead in different millenniums are stated, and therefore when Garga Muni said, “Your son has assumed these colors,” he indirectly said, “He is the Supreme Personality of Godhead.” Because of Kamsa’s atrocities, Garga Muni tried to avoid disclosing this fact, but he indirectly informed Nanda Maharaja that Krsna, his son, was the Supreme Personality of Godhead.
It may be noted that Srila Jiva Gosvami, in his book Krama-sandarbha, has enunciated the Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada of this verse. In every millennium, Krsna appears in a different form, either as white, red or yellow, but this time He personally appeared in His original, blackish form and, as predicted by Garga Muni, exhibited the power of Narayana. Because in this form the Supreme Personality of Godhead exhibits Himself fully, His name is Sri Krsna, the all-attractive.
Factually, Krsna is the source of all avataras, and therefore all the different features of the different avataras are present in Krsna. When Krsna incarnates, all the features of other incarnations are already present within Him. Other incarnations are partial representations of Krsna, who is the full-fledged incarnation of the Supreme Being. It is to be understood that the Supreme Being, whether appearing as sukla, rakta or pita (white, red or yellow), is the same person. When He appears in different incarnations, He appears in different colors, just like the sunshine, which contains seven colors. Sometimes the colors of sunshine are represented separately; otherwise the sunshine is observed mainly as bright light. The different avataras, such as the manvantara-avataras, lila-avataras and dasa-avataras, are all included in the krsna-avatara. When Krsna appears, all the avataras appear with Him. As described in Srimad-Bhagavatam (1.3.26):
avatara hy asankhyeya
hareh sattva-nidher dvijah
yathavidasinah kulyah
sarasah syuh sahasrasah
The avataras incessantly appear, like incessantly flowing water. No one can count how many waves there are in flowing water, and similarly there is no limitation of the avataras. And Krsna is the full representation of all avataras because He is the source of all avataras. Krsna is amsi, whereas others are amsa, part of Krsna. All living entities, including us, are amsas (mamaivamso jiva-loke jiva-bhutah sanatanah). These amsas are of different magnitude. Human beings (who are minute amsas) and the demigods, visnu-tattva and all other living beings are all part of the Supreme. Nityo nityanam cetanas cetananam (Katha Upanisad 2.2.13). Krsna is the full representation of all living entities, and when Krsna is present, all avataras are included in Him.
The Eleventh Canto of Srimad-Bhagavatam describes the incarnations for each yuga in chronological order. The Bhagavatam says, krte suklas catur-bahuh, tretayam rakta-varno’sau, dvapare bhagavan syamah and krsna-varnam tvisakrsnam. We actually see that in Kali-yuga, Bhagavan has appeared in pita-varna, or a yellow color, as Gaurasundara, although the Bhagavatam speaks of krsna-varnam. To adjust all these statements, one should understand that although in some yugas some of the colors are prominent, in every yuga, whenever Krsna appears, all the colors are present. Krsna-varnam tvisakrsnam: although Caitanya Mahaprabhu appears without krsna, or a blackish color, He is understood to be Krsna Himself. Idanim krsnatam gatah. The same original Krsna who appears in different varnas has now appeared. The word asan indicates that He is always present. Whenever the Supreme Personality of Godhead appears in His full feature, He is understood to be krsna-varnam, although He appears in different colors. Prahlada Maharaja states that Caitanya Mahaprabhu is channa; that is, although He is Krsna, He is covered by a yellow color. Thus the Gaudiya Vaisnavas accept the conclusion that although Caitanya Mahaprabhu appeared in pita color, He is Krsna.
krsna-varnam tvisakrsnam
yajñaih sankirtana-prayair
yajanti hi sumedhasah
(Bhag. 11.5.32)


Srimad Bhagavatam Canto 10, Chapter 08, Text 12
Srimad Bhagavatam Canto 10, Chapter 08, Text 14