Jesus Christ Is Lord
To answer the question of whether a Christian can be physically afflicted, we must first explore the means by which devils, demons and evil spirits influence Christians. We cannot continue to abide in sin because of the indwelling nature of Christ. In Ephesians 4:23 Christians are admonished to "be renewed in the spirit of your mind. "If the mind of the Christian needs renewal, then it stands to reason that when our minds are not renewed, they may be, to some degree, under the control of the ungodly forces.
Romans 12:1 says "Present your bodies a living sacrifice, " This means possibly that our bodies may not be completely sacrificed to God, and could therefore be influenced by Satan, Devils and Demons. The lack of spirituality in the life of a Christian doesn't necessarily mean that he or she is oppressed. but it does mean that some part of the Christians's nature is open to evil forces.
In Luke 13:16, Jesus cast a devil out of a daughter of Abraham. It's true she wasn't living under the covenant of grace this side of the cross, but as an Old testament devotee to God, she was spiritually protected by the best that God could offer that side of Calvary. Yet a spirit of physical infirmity demonized her. In fact, the first demon that Jesus cast out came from an apparently devout Jew in the synagogue on the Sabbath. Jesus' first exorcism was in a church! because the demon spoke through a mans body. The Lord Jesus Christ told the unclean spirit to "Come out of him"
Let me explain to you how Satan can also control the thoughts and speech of a Christian. In Matthew, chapter 16 Jesus had just concluded "His" explanation to "His" disciples on the true nature of "His" earthly mission that "He" must suffer and die. Peter immediately spoke up in an effort to dissuade Christ from going to the cross: "Far be it from you Lord; this shall not happen to you! (verse 22) The response of Jesus was abrupt and stern. "Get behind me, Satan! Jesus said to Peter. I'm not suggesting that Peter was demon possessed, I am proposing that Peter, while standing in the presence of Our Lord and Savior Jesus Christ, was sufficiently influenced that he literally spoke the words Satan wanted him to say. Even more astounding is the fact that earlier in verse 16 of this chapter, Peter had given the confessional statement of faith on which Jesus said "He" would build "His" Church!
Can Devils, Demons Physically afflict a Christian?
Do Christian sin?
First John 1:8-10 says we do.
He that committeth sin is of the devil: for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil. Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin because he is born of God. In this the children of God are manifest and the children of the devil: Whosoever doeth not righteousness is not of God. neither he that loveth not his brother.