They made their father drink wine, to wit, in excess, so as to deprive him of the use of his reason and grace, which was likely to frustrate their project: this was a great sin, not only in them, but also in Lot himself, not to be excused by ignorance of the virtue of wine, which being known to both the daughters, certainly their father could not be ignorant of it. Thus he who kept his integrity in the midst of all the temptations of Sodom, falls into a grievous sin in a place where he might seem most remote from all temptations; God permitting this, to teach all following ages how weak even the best men are when they are left to themselves, and what absolute need they have of Divine assistance. He perceived not; wherein there is nothing strange, it being usual with drunken men to do many things in that condition, which, when they come to themselves, they perfectly forget. And so might Lot, when under the power of wine, forget that his wife was turned into a pillar of salt, and might mistake his daughter for his wife.
Related Commentaries of Genesis 19:33
Genesis 19:33
33 And they made their father drink wine that night: and the firstborn went in, and lay with her father; and he perceived not when she lay down, nor when she arose.