Mark 5:12-13 The demons begged Jesus, “Send us among the pigs; allow us to go into them.”  He gave them permission, and the evil spirits came out and went into the pigs.  The herd, about two thousand in number, rushed down the steep bank into the lake and were drowned.
This amazing event in the life and early ministry of Jesus, reported also by both Matthew (8:28-34) and Luke (8:26-39), is extremely confronting, which should not surprise us.  Here we see a head-on collision between the Divine, Eternal Son of God, and Satan’s battalion of forces with which he was trying to dominate and destroy humanity made in the image and likeness of God. Here was the playing out in time and space a part of the supernatural, cosmic conflict that began when Satan first rebelled, and will continue until he is finally put out of action when Jesus returns in power.

The Apostle Paul warns us about the reality and the intensity of this battle: “For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms” (Ephesians 6:12).  It is significant that the event occurred immediately after Jesus had decisively demonstrated his supreme power over the physical forces of nature in the stilling of the storm (Mark 4:37-41), and now he shows that this power rules equally in the spiritual, supernatural realm.

Jesus had already shown his power to forgive sin and to heal sickness and disease (Mark 2:1-12), but this was a totally different situation.  Here was a man actually possessed by demons.  And, according to Matthew and Luke, he was accompanied by another man in a similar state of distress, apparently through no personal fault of their own.

The casting of the battalion of demons OUT of the man and INTO the herd of pigs was to prove that this was something spectacularly different from a ‘normal’ case of healing sickness or disease.  We also see that Jesus’ deep concern for this man’s (these men’s) spiritual health and well-being totally overshadowed his concern for animals that God had created with quite a different purpose in mind (cf Genesis 9:1-3 – “Then [after the flood waters had subsided] God blessed Noah and his sons, saying to them, ‘Be fruitful and increase in number and fill the earth.  The fear and dread of you will fall upon all the beasts of the earth and all the birds of the air, upon every creature that moves along the ground, and upon all the fish of the sea; they are given into your hands.  Everything that lives and moves will be food for you. Just as I gave you the green plants, I now give you everything’”).
– Bruce Christian