But, that we may grant to him in a spirit of candour what he has not discovered in the contents of the book of Genesis, that “the sons of God, seeing the daughters of men, that they were fair, took to them wives of all whom they chose,” we shall nevertheless even on this point persuade those who are capable of understanding the meaning of the prophet, that even before us there was one who referred this narrative to the doctrine regarding souls, which became possessed with a desire for the corporeal life of men, and this in metaphorical language, he said, was termed “daughters of men.”
But whatever may be the meaning of the “sons of God desiring to possess the daughters of men,” it will not at all contribute to prove that Jesus was not the only one who visited mankind as an angel, and who manifestly became the Saviour and benefactor of all those who depart from the flood of wickedness. Then, mixing up and confusing whatever he had at any time heard, or had anywhere found written— whether held to be of divine origin among Christians or not— he adds: “The sixty or seventy who descended together were cast under the earth, and were punished with chains.”
And he quotes (as from the boo of Enoch, but without naming it) the following: “And hence it is that the tears of these angels are warm springs,”— a thing neither mentioned nor heard of in the Churches of God! For no one was ever so foolish as to materialize into human tears those which were shed by the angels who had come down from heaven. And if it were right to pass a jest upon what is advanced against us in a serious spirit by Celsus, we might observe that no one would ever have said that hot springs, the greater part of which are fresh water, were the tears of the angels, since tears are saltish in their nature, unless indeed the angels, in the opinion of Celsus, shed tears which are fresh.
Source: Against Celsus (New Advent)