Luke records the incident of Jesus quieting the storm on the Sea of Galilee immediately following Jesus’ remark concerning who his true family is. Jesus claimed his (spiritual) family is made up of those who both hear and do the word of God. An interesting point is brought out by Dr. Robert Utley in his commentary on Luke 8:21: “This reflects the Hebrew word Shema (cf. Deuteronomy 5:1; 6:4), which means hear so as to do (cf. Luke 11:28)…” The Shema (Deuteronomy 6:4) is the beginning of a great Jewish prayer recited twice daily.
According to Jesus, one couldn’t simply hear what he had to say and be his disciple. After all, Jesus enemies were able to do that, and they would never claim to be one of Jesus’ disciples? Rather, it is required of a disciple of Jesus not only to hear or listen to what he said, as though we were a polite audience, but also to do what Jesus said. A disciple is a dynamic listener; that is, he puts what he has heard into practice.
Jesus had never before or since carried on a conversation with a demoniac, so it is quite odd that he would do so here (cf. Luke 8:29-32; Matthew 8:32). If demons are living sentient beings, who inhabit the bodies of men, there is no real reason why Jesus would carry on a conversation with one. On the other hand, demoniacs are presented in the New Testament as people in need of healing. A demoniac was brought into his present condition either by sin or through some physical, emotional or mental malfunction. It appears in the case of the demoniac of Luke 8 that he was afraid of judgment, so his condition was probably brought about through his guilt over his sins. Therefore, Jesus talked to the man in order to help him receive his healing.
The demoniac’s problem lay in his thinking Jesus was about to kill him, a judgment he considered he deserved, and which the Messiah was thought to administer. The situation becomes even more complex in that the Pharisaic doctrine, which the demoniac believed, falsely inferred torments in hell or the grave (Luke 16:23). His condition demanded that Jesus take other measures that would permit the man to accept his healing.
Jesus began by asking the man his name (Luke 8:30, but the unclean spirit had deprived the man of his identity. Instead of a name, the man offered Jesus a number—legion. A legion consists of 3000 to 6000 men, but probably the word refers to the numerous times the unclean spirit had caught (G4884) the man (cf. Luke 8:29).
The demoniac asked that Jesus would not command his death, but that his unclean spirit would be allowed to live among the swine that were nearby (Luke 8:27, 31-32). If this unclean spirit were a fallen angel, as is often supposed, Jesus would have no reason to comply with the demoniac’s request (Luke 8:32). However, since the man was in such great need of healing, and his guilt over his sins was preventing his healing, Jesus did as the demoniac asked. This also enabled Jesus to show the demoniac that, not only was the unclean spirit that was in him gone, but the man’s sins were forgiven and cast into the sea (Micah 7:19). Thus, the man could now receive his healing.
Immediately, the swine rushed over a steep precipice (Luke 8:33-34; Matthew 8:32) and perished in the sea. The keepers of the swine became afraid and ran and told the townspeople about what had occurred. Then, the townsfolk came out to where Jesus was and saw what was done both to the man, now in his right mind (Luke 8:35), and to the heard of swine. But, when they heard from the keepers how this was done, they also became afraid and asked Jesus to leave their country (Luke 8:35-37).
On the other hand, the man, now in his right mind, wanted to leave with Jesus (Luke 8:35, 38), but Jesus told him to stay and return to his home and tell his friends (Luke8:39; Mark 5:19) what the Lord God had done for him. The man did return, and he published what Jesus did for him throughout the city (Luke 8:39) and the Decapolis (Mark 5:20)! In other words he heard Jesus’ words and did what Jesus said. He was not only a hearer but also a doer – he heard so as to do (the believer’s Shema).
 The Hebrew word Shema (H8085) simply means “hear” in English, but as shown in Deuteronomy 5:1-2, it implies action. That is, Israel was not simply to hear so as to monitor what God said to do, but to hear and do what God commanded (cf. Deuteronomy 9:1 and 20:3). It would do no good for Israel to simply hear that a conflict with their enemies lay between them and possessing the Promised Land. It is required that they go in and possess the land and take part in the conflict wherever necessary.