1 Samuel 19:13

And not in war only, but also in peace the need of deceit may be found, not merely in reference to the affairs of the state but also in private life, in the dealings of husband with wife and wife with husband, son with father, friend with friend, and also children with a parent. For the daughter of Saul would not have been able to rescue her husband out of Saul's hands except by deceiving her father. And her brother, wishing to save him whom she had rescued when he was again in danger, made use of the same weapon as the wife.

Now Michal's name means "reign," because sin reigned over our nature up to that time. And at the very time he himself was born, he [the Lord in the figure of David] went out through a window. And the window indicates the return to the light again of the one who made himself known to those sitting in darkness and the shadow of death.And his image is seen on the bed. For the angel says to those seeking the Lord in the tomb, "Why do you seek the living with the dead? He is not here; he is risen." "Behold the place" in which he lay. Those seeking the Lord saw the tomb in which he was buried empty of the body of the one they were seeking. Only the burial sheets were in it. We think, therefore, that the image of David on the bed signifies the resurrection of the Lord in the tomb, through which the true averting of our death through expiatory sacrifice occurs.

But Michal took an image and laid it on the bed, etc. The history of the hairy skin, of the skins of goats, is evident; for there was a cushion sewn of goat's skin, which, with its unshorn hairs, feigned the head of a man lying in bed. The statue, however, is an imitation of the true and living; the dead skin of goats is the remains of a dead animal. Therefore, Michal took an image and placed it on David's bed, as he was let down through the window and secretly saved. The Church learned to regard the Jews' Lord, who was laid in the sepulcher, not as Christ, life and truth, but as a likeness of truth and life, declaring himself to be Christ the king. The Church is said to do this in the true manner of speaking, for it bears witness to the deeds done or to be done by the ungodly, as it is written in Leviticus, "Behold, the priest shall declare him unclean" (Lev. 13): not because he could bring leprosy to the clean, but to show what was already present in the unclean. Also, Michal placed the hairy skin of goats at the head of the statue. The Church, at its beginning, discovered the perfidy even of those who not only deny the Lord Savior as Christ but also claim he was burdened with sins, not resurrected from the dead. For it is certain that the goat often holds the type of a sinner, just as a sheep does that of the just. The hairs, brittle and externally superfluous to the body, signify dead works, becoming manifest due to their density and frequency. They place the hairy skin of goats at the head of the statue set up in the bed for David, asserting the flesh of the Savior to be rough and impure due to mortal sins, saying that until now it still holds the bed of the sepulcher, into which he descended dead. However, Michal covers the statue with garments, which the Church, after recognizing such perfidy, rejects; after showing it to the faithful, it immediately demonstrates it condemned and vanquished through outstanding works that no one else could accomplish.