1. Jesus commanded it. We know it is God's will for His servants to cast out demons, for it is His command: "Heal the sick, raise the dead, cleanse lepers, cast out demons. You received without paying; give without pay." (Matthew 10:8 ESV)
2. Casting out demons was integral to Jesus' discipleship model. The disciple's job description is outlined in Mark 3:14-15:
"And he appointed twelve (whom he also named apostles) so that they might be with him and he might send them out to preach 15 and have authority to cast out demons." (Mark 3:14-15 ESV)
For many years God drew me closer to Himself through a campus ministry with the following vision: “A movement of students who have alive walks with Christ and are in authentic relationships as we advance the gospel to every person.” (1)
This vision statement guided my prayer life and goals for those many years, for it closely resembles Mark 3:14. Jesus appointed his disciples to have alive walks with him (“so that they might be with him”), to be in authentic relationships with him and each other as they did life together, and to advance the gospel of the kingdom (“and he might send them out to preach”).
Later, by God's grace, I realized that Mark 3:15 adds another vital aspect of Jesus’ purpose for his disciples then and now: “and have authority to cast out demons.”
Having authority to cast out demons isn't merely an addition to the discipleship aspects of Mark 3:14; it also enriches them. From my own experience, I can testify that casting out demons when they happen to manifest increases my awe and love for Christ, adding an exciting vibrancy to my relationship with Him. Likewise, it tightens the bond of authentic relationships I have with my brothers and sisters in Christ as we battle together in spiritual warfare. C.f. Ephesians 6:12. I imagine that it was no different for Jesus’ disciples and the early church.
3. Casting out demons is part of the Great Commission. And he said to them, "Go into all the world and proclaim the gospel to the whole creation. Whoever believes and is baptized will be saved, but whoever does not believe will be condemned. And these signs will accompany those who believe: in my name they will cast out demons; they will speak in new tongues; they will pick up serpents with their hands; and if they drink any deadly poison, it will not hurt them; they will lay their hands on the sick, and they will recover." (Mark 16:15-18 ESV) And Jesus came and said to them, "All authority in heaven and on earth has been given to me. Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age." (Matthew 28:18-20 ESV) In Matthew 28:20, Jesus commands his disciples to teach their disciples to "observe all that I have commanded you." [Emphasis mine.] What then are all the commandments that he commanded them? The word "all" necessarily includes his commandments in Matthew 10:8: "Heal the sick, raise the dead, cleanse lepers, cast out demons. You received without paying; give without pay."
As God’s slaves, we cannot pick and choose which of His orders to follow to suit our convenience. If God wants us to cast out demons, heal the sick, etc. for His glory, then we need to have a submissive, teachable attitude like Mary demonstrated in Luke 1:38:
“...Behold, I am the servant of the Lord; let it be to me according to your word…”
4. It's a practical way to "love your neighbor as yourself."
All God’s commandments can be summarized in just two commandments:
“And one of them, a lawyer, asked him a question to test him. 36 ‘Teacher, which is the great commandment in the Law?’ 37 And he said to him, ‘You shall love the Lord your God with all your heart and with all your soul and with all your mind. 38 This is the great and first commandment. 39 And a second is like it: You shall love your neighbor as yourself. 40 On these two commandments depend all the Law and the Prophets.’” (Matthew 22:35-40 ESV)
If you were demonized and you knew it, wouldn't you want someone to help fight with you for deliverance by casting the demon(s) out through Christ by the power of the Holy Spirit? Jesus said, "So whatever you wish that others would do to you, do also to them, for this is the Law and the Prophets."
(Matthew 7:12 ESV) Which is more loving: (1) To cast out demons or (2) to leave them inside?
Whenever Jesus cast out demons and healed the sick, he did it because he loved people, had compassion on them, and wanted them to know God the Father’s love for them. That’s why he forgave all their sin and healed all their diseases. C.f. Psalm 103:3; Mark 2:1-12; Isa. 53:4-5. His kindness led them to repentance as they put their faith in him, submitted their allegiance to him, and followed him. C.f Romans 2:4; 10:9-10.
5. Casting out demons is a demonstration of the gospel.
During Jesus’ “inaugural address” for his ministry, he read from Isaiah 61:1:
"The Spirit of the Lord is upon me, because he has anointed me to proclaim good news to the poor. He has sent me to proclaim liberty to the captives and recovering of sight to the blind, to set at liberty those who are oppressed…” (Luke 4:18 ESV)
As demonstrated by Jesus and the early church, casting out demons demonstrates the power and love of God.
“For the kingdom of God does not consist in talk but in power.” (1 Corinthians 4:20)
Why did Jesus come to earth? What is the good news (gospel)?
“For even the Son of Man came not to be served but to serve, and to give his life as a ransom for many.’" (Mark 10:45 ESV)
“For the Son of Man came to seek and to save the lost.’" (Luke 19:10 ESV)
“Whoever makes a practice of sinning is of the devil, for the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the works of the devil.” (1 John 3:8 ESV)
As we see from these verses, Jesus came to seek and save the lost, to give his life as a ransom for many, and to destroy the devil's work.
He gives his followers the authority to continue his work until people from every tongue, tribe, and nation believe the good news that Jesus is King of the universe. C.f. Luke 10:19-20; Matthew 24:14; Revelation 5:9ff.
Jesus’ power, authority, and love is demonstrated through his followers doing the works Jesus did and even greater by the power of the Holy Spirit. C.f. John 14:10-17; Acts 1:8; Acts 2:38f.
Those works include healing the sick and casting out demons through Jesus Christ by the power of the Holy Spirit to the glory of God the Father. C.f. Acts 10:38; 1 John 2:6.
(1) Sioux Empire Cru vision statement
