from 'Against Heresies' by Irenaeus, disciple of Polycarp, disciple of the apostle John, ~ 180 AD
book IV chapter 31
1. When recounting certain matters of this kind respecting them of old time, the presbyter [before mentioned] was in the habit of instructing us, and saying: With respect to those misdeeds for which the Scriptures themselves blame the patriarchs and prophets, we ought not to inveigh against them, nor become like Ham, who ridiculed the shame of his father, and so fell under a curse; but we should [rather] give thanks to God in their behalf, inasmuch as their sins have been forgiven them through the advent of our Lord; for He said that they gave thanks [for us], and gloried in our salvation. With respect to those actions, again, on which the Scriptures pass no censure, but which are simply set down [as having occurred], we ought not to become the accusers [of those who committed them], for we are not more exact than God, nor can we be superior to our Master; but we should search for a type [in them]. For not one of those things which have been set down in Scripture without being condemned is without significance. An example is found in the case of Lot, who led forth his daughters from Sodom, and these then conceived by their own father; and who left behind him within the confines [of the land] his wife, [who remains] a pillar of salt unto this day. For Lot, not acting under the impulse of his own will, nor at the prompting of carnal concupiscence, nor having any knowledge or thought of anything of the kind, did [in fact] work out a type [of future events]. As says the Scripture: And that night the elder went in and lay with her father; and Lot knew not when she lay down, nor when she arose. Genesis 19:33 And the same thing took place in the case of the younger: And he knew not, it is said, when she slept with him, nor when she arose. Genesis 19:35 Since, therefore, Lot knew not [what he did], nor was a slave to lust [in his actions], the arrangement [designed by God] was carried out, by which the two daughters (that is, the two churches ), who gave birth to children begotten of one and the same father, were pointed out, apart from [the influence of] the lust of the flesh. For there was no other person, [as they supposed], who could impart to them quickening seed, and the means of their giving birth to children, as it is written: And the elder said to the younger, And there is not a man on the earth to enter in unto us after the manner of all the earth: come, let us make our father drunk with wine, and let us lie with him, and raise up seed from our father. Genesis 19:31-32
2. Thus, after their simplicity and innocence, did these daughters [of Lot] so speak, imagining that all mankind had perished, even as the Sodomites had done, and that the anger of God had come down upon the whole earth. Wherefore also they are to be held excusable, since they supposed that they only, along with their father, were left for the preservation of the human race; and for this reason it was that they deceived their father. Moreover, by the words they used this fact was pointed out — that there is no other one who can confer upon the elder and younger church the [power of] giving birth to children, besides our Father. Now the father of the human race is the Word of God, as Moses points out when he says, Is not He your father who has obtained you [by generation], and formed you, and created you? At what time, then, did He pour out upon the human race the life-giving seed — that is, the Spirit of the remission of sins, through means of whom we are quickened? Was it not then, when He was eating with men, and drinking wine upon the earth? For it is said, The Son of man came eating and drinking; Matthew 11:19 and when He had lain down, He fell asleep, and took repose. As He does Himself say in David, I slept, and took repose. And because He used thus to act while He dwelt and lived among us, He says again, And my sleep became sweet unto me. Jeremiah 31:26 Now this whole matter was indicated through Lot, that the seed of the Father of all — that is, of the Spirit of God, by whom all things were made — was commingled and united with flesh — that is, with His own workmanship; by which commixture and unity the two synagogues— that is, the two churches — produced from their own father living sons to the living God.
3. And while these things were taking place, his wife remained in [the territory of] Sodore, no longer corruptible flesh, but a pillar of salt which endures for ever; and by those natural processes which appertain to the human race, indicating that the Church also, which is the salt of the earth, Matthew 5:13 has been left behind within the confines of the earth, and subject to human sufferings; and while entire members are often taken away from it, the pillar of salt still endures, thus typifying the foundation of the faith which makes strong, and sends forward, children to their Father.