“Tertullian (d. 225AD) wishing, in the De Baptismo, to justify the use of water in Baptism from the unbroken witness of the Bible, turned first to the story of Creation in Genesis. In this narrative, the waters have two characteristics which Baptism reproduces: it is the primordial element in which life appears, and it is sanctified by the Holy Spirit. Tertullian develops this first aspect:
‘First of all, O man, you should have reverence for the antiquity of the waters as a primordial element’ (Bapt. 2).
It was in the midst of the waters that the earth appeared:
‘Once the elements of the world were set in order, when it was to be given inhabitants, it was the primordial waters which were commanded to produce living creatures. The primordial water brought forth life, so that no one should be astonished that in Baptism the waters are able to give life.’ (Bapt. 2).
And to this characteristic, another is added: the fact that the
‘Spirit of God was carried over the waters, He Who was to recreate the baptized. The Holy One was carried over that which was holy, or, rather, over that which could receive holiness from Him Who was carried. It is thus that the nature of water, sanctified by the Spirit, received the capability of itself becoming sanctifying. This is why all waters, by reason of their ancient original prerogative, may obtain the sacrament of sanctification by the invocation of God’ (Bapt. 2).
What is taught here is the consecration of the baptismal water, to which ancient Christianity attached great importance:
‘You have seen water. But all water does not heal, if the Spirit has not descended and consecrated that water.’ (Ambrose, De Sacr. 1, 15; Botte; 58).”
(Jean Danielou, S.J, The Bible and the Liturgy, pp 72-73)