Our Gemara on amud refers to the principle of stam kinyan lekesiva omed:

A symbolic act of acquisition indicates one’s intention to do everything possible to finalize the transaction as soon as possible without waiting for the actual transfer of the item. Therefore, it is assumed that the parties would desire that a document be written, and no explicit authorization is necessary.  

When the Gemara uses the term kinyan, it often refers to kinyan sudar, which is usually accomplished by exchanging a small object of clothing.  This is epitomized in Megilas Rus (4:7) whereby Boaz used this symbolic act of confirmation to assume the rights of the closest relative in order to marry Rus and redeem the fields that were part of Abimelech’s estate.  According to Likkutei Halachos, money represents the feminine quality such as emotion and desire which is in a less formed impractical state, while the physical act of acquisition via kinyan sudar represents an enactment and concretization of the feminine perceptions, feelings and instincts.  This is why that symbolic acts leads to a contract, which is the concretization of words into physical space. 

The kinyan sudar, which is first introduced to us in Megillas Rus (ibid) as a removal and transfer of an article of clothing, na’alo, which some translate as shoe, literally means enclosure, and so can be clothing or a vessel.  The use of an enclosure or shoe to marry Rus, and even its presence in the chaliztah ceremony (Devarim 25:9) is not lost on the Zohar. The enclosure is the woman who helps the man find a physical clothing or space to animate the emotions that heretofore were unmaterialized potential. As we discussed in a prior blog post, the Zohar in the beginning of Parashas Chukas makes a comparison between kinyan sudar, Levirate Marriage, and finally transmigration and reincarnation. They are one in the same, as they represent transfers from spiritual to physical - every form of possession. Selling an object requires a ritual as much as chalitzah and divorce. In other words, to the mystical mindset, everything is connected from the most inanimate object to the human soul, and they are brought to life by human actions and God’s spiritual flow.