The term "covenant" usually refers the major covenants in the Old Testament between God and the Israelites.  Four of these Covenants are considered major and are give their own definitions, while the other four are covered in the Biblical Covenants.

There are four methods used in the Bible to ratify a covenant.  They are ordered from the least binding to the most binding form of commitment to the covenant ¹.

1. Hand Covenant
   Much like the handshake of today, two parties would shake hands or strike the palms of their hands together.  (Ezra 10:19; Eze. 17:18)
2. Shoe Covenant
   The two parties would exchange sandals signifying that the covenant was in effect until the sandals were returned.  Boaz made this type of covenant with the kinsman-redeemer to redeem Ruth (Ruth 4:8).
3. Salt Covenant
   Because salt was vital to every traveler in Biblical times (it prevents dehydration and allows the body to retain moisture), each carried a pouch that they would carry around their waste.  Once the terms of a covenant had been agreed upon, each party would put a small pinch of salt in the others pouch.  This signified that the covenant could only be broken if the exact grains of salt were returned to the original owner. (God made several of these with the Israelites Lev. 2:13; Num. 18:19; 2 Chr. 13:5)
4. Blood Covenant
   After the terms were settled an animal was divided in half through its median plane and laid out on the ground.  Both parties would grasp hands, recite the terms and walk together between the pieces of the carcass.  This was the most severe and serious of the covenants.  It signified that the party that broke the covenant would have the same thing done to them as to the animal - it carried the death penalty.  The animal's death also represented the permanancy of the terms of the covenant.  The two parties could alter the terms while they were alive, but once dead they could not change them.  The animal represented the death of both parties, meaning that the covenant was unchangeable.