Now, if they ask, Why then did He not appear by means of other and nobler parts of creation, and use some nobler instrument, as the sun, or moon, or stars, or fire, or air, instead of man merely? Let them know that the Lord came not to make a display, but to heal and teach those who were suffering. For the way for one aiming at display would be, just to appear, and to dazzle the beholders; but for one seeking to heal and teach the way is, not simply to sojourn here, but to give himself to the aid of those in want, and to appear as they who need him can bear it; that he may not, by exceeding the requirements of the sufferers, trouble the very persons that need him, rendering God's appearance useless to them.
Now, nothing in creation had gone astray with regard to their notions of God, save man only. Why, neither sun, nor moon, nor heaven, nor the stars, nor water, nor air had swerved from their order; but knowing their Artificer and Sovereign, the Word, they remain as they were made. But men alone, having rejected what was good, then devised things of nought instead of the truth, and have ascribed the honour due to God, and their knowledge of Him, to demons and men in the shape of stones. With reason, then, since it were unworthy of the Divine Goodness to overlook so grave a matter, while yet men were not able to recognise Him as ordering and guiding the whole, He takes to Himself as an instrument a part of the whole, His human body, and unites Himself with that, in order that since men could not recognise Him in the whole, they should not fail to know Him in the part; and since they could not look up to His invisible power, might be able, at any rate, from what resembled themselves to reason to Him and to contemplate Him.
-- St. Athanasius of Alexandria, On the Incarnation, 43.1-4