We read in the fifth book of Moses Deut. 25.5-10 that the unmarried brother of a deceased man who is without issue shall marry his sister-in-law, and raise up an heir and seed unto his brother, in order to preserve his line and name, and so that the property should not come to a foreign line. However, if he refuses to marry her, she must denounce him to the elders and councillors, draw off from him a shoe to indicate that he has lost the right to his brother's line. She must spit in his face and say: Thus shall it be done to him who will not build up his brother's wife etc.
Subsequently the rabbis ordained that there should be no more marriages to a dead brother's wife, but they should separate through the drawing off of the shoe, which separation was called by them Chalitza.
It goes like this: The wife summons five unrelated witnesses together before the chief Rabbi, as well as her brother-in-law. The rabbi asks the wife:
Then he asks the brother:
He responds, No, I do not wish to marry her. The shoe is then brought: it is made in a special way, with flaps, strings, and loops. Then he puts it on his uncovered right foot, and leans against a wall. The woman comes up to him and says: This brother-in-law of mine will not raise up a name for his brother, so he should no longer be called my brother-in-law. She stoops down, with her right hand takes off his shoe, draws it from his foot, and spits in his face so hard that the five witnesses can see the spittle, and says: Thus shall be done to the man, who will not build up his brother's house. The judges and all the bystanders cry out: Chalutz hannahal the shoe is drawn off. And thus they are separated.
The Rabbis have a major question if such a woman has no right hand. How should she draw off the shoe? Some permit her to use her teeth in such a case.
If the brother-in-law will not undergo this shame, and the widow wishes to marry another man, oftentimes she will have to pay her brother-in-law a tidy sum of money to persuade him to release her. If the brother-in-law lives in another city, it is incumbent upon her to follow him, and seek her release from him.
The Pharisees asked Christ in respect to this custom Matthew 22.23-28: If seven brothers married one wife [in succession, as each died] whose wife would she be at the resurrection? You can see that at that time brothers still married their sister-in-law.