adityanam aham vishnur
jyotisam ravir amsuman
maricir marutam asmi
nakshatranam aham sasi

"Of the Adityas I am Vishnu, of lights I am the radiant sun, of the Maruts I am Marici, and among the stars I am the moon."

He cites many groups. Adityana = among the Adityas, aham = I [Sri Krishna] am, vishnu = Vishnu. Kashyapa had two wives Dhiti and Adhiti. Adhiti gave birth to Tweleve Adityas, in which Vishnu was the youngest. This Vishnu should not be mistaken as Lord Vishnu. Each one of these Twelve Adityas, go round our Earth one month in an year. It starts in the month of Margazhi and ends in Karthigai. The Lord says to Arjuna that among the Adityas, He is the youngest and most important Vishnu. Here, Sri Krishna mentions Himself [Aham] and Vishnu in the same nominative case. In both sarira-atman bhavam and karana-karya bhavem, both can be mentioned in the same nominative case, as in the example mud pot. Here, therefore, it means that He is the soul of Vishnu or He is the creator of Vishnu. In fact all Adityas are the body of the Lord and all of them were created by the Lord. Jyotisam = among the luminous objects, ravi = the Sun, amsuman = with rays. We regard Sun as the most radiant among luminous objects; and the Lord says He is the Sun. Marutham = among the Maruths, marici = [the Lord is] Marichi. Dhiti and Adhti were the wives of Kashyapa. Dhitis children were all Asuras and so are called Dhaiteyas. Adhiti's children were Devas. When Dhiti was pregnant, Indra, the leader of Devas, wanted to destroy the child in her womb so that there would not be more Asuras. But in doing so, the foetus got split into Seven. Indra again tried to destroy all the Seven foetus, but they became Seven times and 49 children were born to Dhiti. They are called Maruths, which literally mean air. Of the group of 49 Maruths, the Lord is Marichi. Nakshatranam = among Stars, sasi = Moon. According to Sanskrit grammar, the instrumental case [Sixth case] two relationships are possible. One is nirdharanesakti and the other is sambandha samanysakti. All previous objects were in the first relationship. But in this, that relationship can not be applied and we have to apply the second category. Among Adityas, the Lord is Vishnu, as Vishnu is also an Aditya. But Moon is not a star and is different. Here Moon is the leader and stars are deputies. This relationship is to be considered here. Depending on the context we have to carefully apply these relationships. The Lord dwells in Moon as the atman; and the Lord is the Cause for Moon; so the Lord is Moon. All are His property or all are at His command. He is going to list more in the ensuing slokas.