[HerenIstarion]

Some interesting stuff to take a look at:

From Osanwe-Kenta

Here Pengoloð adds a long note on the use of hröar by the Valar. In brief he says that though in origin a "self-arraying", it may tend to approach the state of "incarnation", especially with the lesser members of that order (the Maiar). "It is said that the longer and the more the same hröa is used, the greater is the bond of habit, and the less do the 'self-arrayed' desire to leave it. As raiment may soon cease to be adornment, and becomes (as is said in the tongues of both Elves and Men) a 'habit', a customary garb. Or if among Elves and Men it be worn to mitigate heat or cold, it soon makes the clad body less able to endure these things when naked". Pengoloð also cites the opinion that if a "spirit" (that is, one of those not embodied by creation) uses a hröa for the furtherance of its personal purposes, or (still more) for the enjoyment of bodily faculties, it finds it increasingly difficult to operate without the hröa. The things that are most binding are those that in the Incarnate have to do with the life of the hröa itself, its sustenance and its propagation. Thus eating and drinking are binding, but not the delight in beauty of sound or form. Most binding is begetting or conceiving.
"We do not know the axani (laws, rules, as primarily proceeding from Eru) that were laid down upon the Valar with particular reference to their state, but it seems clear that there was no axan against these things. Nonetheless it appears to be an axan, or maybe necessary consequence, that if they are done, then the spirit must dwell in the body that it used, and be under the same necessities as the Incarnate. The only case that is known in the histories of the Eldar is that of Melian who became the spouse of King Elu-thingol. This certainly was not evil or against the will of Eru, and though it led to sorrow, both Elves and Men were enriched.

'The great Valar do not do these things: they beget not, neither do they eat and drink, save at the high asari, in token of their lordship and indwelling of Arda, and for the blessing of the sustenance of the Children. Melkor alone of the Great became at last bound to a bodily form; but that was because of the use that he made of this in his purpose to become Lord of the Incarnate, and of the great evils that he did in the visible body. Also he had dissipated his native powers in the control of his agents and servants, so that he became in the end, in himself and without their support, a weakened thing, consumed by hate and unable to restore himself from the state into which he had fallen. Even his visible form he could no longer master, so that its hideousness could not any longer be masked, and it showed forth the evil of his mind. So it was also with even some of his greatest servants, as in these later days we see: they became wedded to the forms of their evil deeds, and if these bodies were taken from them or destroyed, they were nullified, until they had rebuilt a semblance of their former habitations, with which they could continue the evil courses in which they had become fixed". (Pengoloð here evidently refers to Sauron in particular, from whose arising he fled at last from Middle-earth. But the first destruction of the bodily form of Sauron was recorded in the histories of the Elder Days, in the Lay of Leithian.)