The Shikshavalli of the Taittiriya Upanishad mentions:
भूरिति वा अग्निः । भुव इति वायुः । सुवरित्यादित्यः । मह इति चन्द्रमाः । चन्द्रमासा वाव सर्वाणि ज्योतीँषि महीयन्ते ।
Why is moon equated with the Vyahriti Mahah? It is not that the luminaries derive their glory from the moon because it is well known that the sun empowers the luminaries.
I found an alternative explanation here. The explanation that Agni, Vayu, Aditya respectively represent the tongue, the ears, and the eyes and that the moon represents the manas and that the manas is the controller of the senses seems to make some sense although I do not understand why only these three are picked. Also, if this correlation were to be accepted, later, in the same Upanishad, we find a section on PAnkta UpAsana (meditation on quintets) where, according to some schools, the three groups of quintets in the external world (macrocosm/universal body) are to be correlated with the three groups of quintets in the internal world (microcosm/body). If such a correlation were to be brought between the "agnir, vayur, adityas, chandrama, nakshatrani" in the macrocosm and the quintet "chakshus srotram mano vak tvak" in the microcosm, then, although there is a correlation between the first two, I am not able to draw a further correlation between the rest of the elements.