(Note: This post is a continuation of part 23, and you can read it here.)
Our verse today is one of those that has been part of a controversy in the church because of the ones who have interpreted it, in conjunction with Mark 16, to suggest that "true believers" of Christ can handle serpents (rattlesnakes and other poisonous snakes) without harm, even when a snake bite results in envenomation. When we look at this passage in context, however, I believe we will see it a little differently. The seventy sent-ones had just returned from their journey of sharing the good news of Jesus and healing the sick. They were filled with joy over the results of their labors and rejoiced that "even the demons are subject to us in Your name."
They rejoiced in what they saw with their physical eyes. Jesus, however, shared and rejoiced in what He saw with His spiritual eyes. "I was watching Satan fall from heaven like lightning." Immediately following that statement, He said, "Behold, I have given you authority to tread on serpents and scorpions, and over all the power of the enemy, and nothing will injure you." Because Jesus was speaking in the previous sentence from a spiritual perspective, He was almost certainly continuing in a spiritual perspective.
"And I will put enmity between you and the woman, and between your seed and her seed; He shall bruise you on the head, and you shall bruise him on the heel." Geneses 3:15 NASB
Clearly, the heel of Christ and the head of the serpent Satan have a figurative encounter here. Although the serpent Satan will deliver a bruise to Christ's heel, it will not be a terminal wound. The heel of Christ, however, will "bruise" the head of Satan, delivering a fatal blow. (If the head is crushed, it is fatal.)
Let's put all this rambling together. When we serve Christ in obedience as the seventy sent-ones did, we participate in destruction of the kingdom of the evil one. Christ has given his obedient followers the authority to "