One of the Old Testament readings for the feast of Theophany is Genesis 1:1-13 which describes the first three days of creation. St. Basil the Great comments on verse 2 of Genesis 1:
“ ‘And the spirit of God,’ he says, ‘was stirring above the waters.’ (Genesis 1:2)
If this spirit means the diffusion of the air, understand that the author is enumerating to you the parts of the world, saying that God created the heavens, the earth, water, and air; and this latter was spreading and flowing. Or, what is truer and approved by those before us, the Holy Spirit is called the Spirit of God, because it has been observed that It alone and specially was considered worthy by the Scripture of such mention, and there is named no other Spirit of God than the Holy Spirit which forms an essential part of the divine and blessed Trinity. Admitting this meaning, you will find the advantage from it great.
How, then, was It stirring above the waters? I will tell you an explanation, not my own, but that of a Syrian who was as far removed from worldly wisdom as he was near the knowledge of truth. Now, he claimed that the language of the Syrians was more expressive and because of its resemblance to the Hebrew language approached somewhat more closely to the sense of Scripture; therefore, the meaning of the statement was as follows. As regards the verb ‘was stirring above,’ they interpret in preference to that, he says, ‘warmed with fostering care,’ and he endued the nature of the waters with life through his comparison with a bird brooding upon eggs and imparting some vital power to them as they are being warmed.
Some such meaning, they say, was implied by this word, as if the Spirit were warming with fostering care, that is, was preparing the nature of water for the generation of living beings. Therefore, from this there is sufficient proof for the inquiries of certain men that the Holy Spirit is not wanting in the creative power.” ( The Fathers of the Church: Exegetic Homilies, pp 30-31)
St. Basil turns to philology to help understand the imagery of the Holy Spirit hovering over the waters – he is told that in the Syrian language the words imply by this hovering over the waters a image more that of a mother bird nesting on her eggs to warm them and to bring them to birth. The Holy Spirit is seen as in some manner vivifying the inanimate waters so that they creatively bring forth life. God is able from inanimate matter to bring forth life.