On the Creation of Magistrates (1.106-1.110)

But the woman who has had experience of another husband is very naturally less inclined to obedience and to instruction, inasmuch as she has not a soul perfectly pure, like thoroughly smooth wax, so as to receive distinctly the doctrines which are to be impressed upon it, but one which is to a certain degree rough from the impressions which have been already stamped upon it, which are difficult to be effaced, and so remain, and do not easily receive any other impression, or if they do they render it confused by the irregularity of their own surface.

Let the high priest, therefore, take a pure virgin to be his wife; I say a virgin, meaning not only one with whom no other man has ever been connected, but one in connection with whom no other man has ever been named in reference to the agreement of marriage, even though her body may be pure.

But besides this, injunctions are given to the particular and inferior priests concerning their marriages, which are the very same in most points, which are given to those who have the supreme priesthood. But they are permitted with impunity to marry not only maidens but widows also; not, indeed, all widows, but those whose husbands are dead. For the law thinks it fitting to remove all quarrels and disputes from the life of the priests. And if they had husbands living there very likely might be disputes from the jealousy which is caused by the love of men for women. But when the first husband

And even on other accounts he might have thought that the high priest ought to be of superior purity and holiness, as in other matters so also in the connection of marriage, and on this account it may have been that God only allowed the high priest to marry a virgin. But to the priests of the second rank he remitted something of the rigour of his regulations concerning the connection with women, permitting them to marry women who have made trials of other husbands.

And besides these commands, he also defined precisely the family of the women who might be married by the high priest, commanding him to marry not merely a woman who was a virgin, but also one who was a priestess, the daughter of a priest, that so both bridegroom and bride might be of one house, and in a manner of one blood, so as to display a most lasting harmony and union of disposition during the whole of their lives.