In Tennessee, three documents were created at the time of a marriage.

The first was the marriage bond.
The second was the license, wherein the court authorized the marriage, and the official signed the back to show that it had been performed.
The ledger where the clerk copied some information from these two sources is known as the official marriage record, and is often the only surviving part of the record.

The groom had to assure the State that he was able to be legally married (was not already married to someone else, under age, or ineligible because of close blood relationship, etc.)
This assurance was given in the form of a bond for a certain amount of money. The friend or relative signed as the groom's security on the bond, commonly known as becoming a bondsman.
If indeed the groom had been sued for violating the marriage contract, the bondsman would have had to pay any legal damages if the groom defaulted.
No money actually changed hands at the time the bond was issued.
This bonding procedure was used across Tennessee and in other southern states in the 19th century.