We know from Gen 3:14-15 God put enmity between the offspring of the serpent and the offspring of Eve. Eventually her seed would crush the serpent's head in Christ's victory over Satan. Satan's seed began with Cain (1 John 3:12) and after the flood continued in Esau and his decendents. Caiaphas, the chief priests and temple guards were Edomites, they were the seed of the serpent who struck Christ's heel. The tribe of Dan was called to provide justice for his people, but later they became trecherous and betrayed the tribe of Judah. Dan's betrayal was likened to a serpent waiting along a path to throw down the rider by striking the horses heels (Gen. 49:16-17). For a sum of thirty silver pieces, Judas collaborated with the chief priests to have Jesus arrested. His betrayal became the fulfillment of the serpent striking the horses heels. As the rider fell from his position so did Jesus fall from Rabbi to a criminal. Judas handed Jesus over to the Edomites who crucified him as protrayed in the serpent striking his heel.