The term spirit of infirmity occurs in Luke 13:11 specifically in the KJV. Here a woman who had been crippled for eighteen years is healed by Jesus on the Sabbath day. Luke says she has a “spirit of infirmity” or a “disabling spirit” (ESV) or a “sickness caused by a spirit” (NASB) or is “crippled by a spirit” (NIV). Quite simply then, this “spirit of infirmity” is a demon who caused the woman to be crippled for eighteen years.
The Bible is clear that spiritual warfare exists. Ephesians 6:12 says, “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.” And, from Luke 13, it is clear that evil spirits can sometimes cause physical maladies. However, it is not clear that there are specific spirits whose “specialty” is such things as sickness or poverty or anger. Luke’s reference to the “spirit of infirmity” indicates that, at least in that one case, a demon had been granted power to inflict a disability. Extrapolating a doctrine that categorizes demons according to the afflictions they cause goes beyond what the Bible teaches.
We need to be careful not to overemphasize the power of demons. Many human ailments are simply caused by living in a fallen world, and there are many instances in Luke’s gospel of people being healed of diseases with no mention of a demonic cause. In Luke 13 Jesus specifically speaks of Satan having bound this woman (verse 16). But, in many other cases of healing, He simply heals with no mention of evil spirits involved.
Today, there are some people who refer to “spirits of infirmity” as being the cause for sickness. Or they may talk about “spirits of” particular emotions or sins, such as anger or lust. Certainly, Satan and his demons can attack our bodies, emotions, and thinking patterns. But we cannot blame every illness or every difficult emotion or every sin on Satan’s influence. There is a variety of reasons a person may be struggling with such things.
No matter the specific cause of an infirmity, we can bring the problem to God in prayer. James 4:7–8 talks about resisting the devil and submitting to God. Prayer is one way to do this. James 5:16 says we should confess our sins to one another so that we can pray for healing.
The major thing to observe from Luke 13:10–17 is the power and compassion of Jesus. In an instant, He overcame the disability this woman had been struggling with for eighteen years. He healed her on the Sabbath day, to the indignation of the Pharisees. He responded to her need with compassion, calling the woman a “daughter of Abraham” (verse 16) and highlighting how much God loved her and was willing to free her.