Jewish marriage consists of two stages—betrothal and marriage. In Hebrew the first stage is termed “kiddushin” in mishnaic Hebre and “erusin” in biblical Hebrew. The second stage is termed “nisuin.” At betrothal the couple become fully and legally connected to one another. The most important consequence is that a get would be required to end their betrothal. Other consequences would include inheritance, breaking of vows and if he is a priest for his becoming impure in order to bury her. Since the connection between the couple is created at the point of betrothal, the laws of betrothal are much more important in halakhah than are the laws of full marriage (nisuin).
Much of our tractate deals with how a woman becomes “mekudeshet”—betrothed—to a man. Basically there are three ways to effect betrothal—money, document or sexual relations. It seems quite clear that betrothal was nearly always affected through the use of money. Today the ring given from the husband to the bride is the money used to affect betrothal.
The rabbis often attempt to learn these three means of betrothal from various verses in the Torah. Without examining these midrashic attempts, we should note that the Torah provides little information as to how betrothal, or marriage for that matter, was contracted. This is typical of the Torah’s laws—the Torah often skips the mundane, every day matters and legislates only the unusual. There may be hints that money and sexual relations are involved in the marital process but their function in the Torah is unusual. It was left for the rabbis to clarify exactly how betrothal was entered into.
Besides the laws of betrothal, there are other laws which are discussed at length in this tractate. Since betrothal is a form of acquisition, whereby a husband acquires a wife, the Mishnah discusses how other things (slaves, animals, land etc.) are acquired. While this chapter seems to consider women to be chattel (possessions), we should note that there are some key differences. The acquisition of women is symbolic, since as we will learn, a woman can be acquired for a symbolic amount of money. Secondly, everything else that a person acquires he may eventually sell. A husband cannot sell his wife. Nevertheless, we should admit that the mishnaic laws of marriage are not egalitarian—the man acquires a woman and the woman does not acquire a man.
The fourth chapter discusses laws of personal status, defining how genealogical ranks are passed down from generation to generation. These laws begin with a mishnah which teaches that Judaism is passed through the mother. When we learn these mishnayot we shall note their connection with betrothal, the main topic of the tractate.
I should note that throughout my commentary on kiddushin, I will intermittently use the words kiddushin and betrothal. Both refer to the same thing, the act by which a man betroths a woman. I will not use the word kiddushin to refer to a couple that is already betrothed.
Good luck in learning Kiddushin!