When God asks: “Is not My word like a fire…?” (Jer. 23:29). He is saying that His word carries the type of power associated with fire. Fire devours, consumes or burns up what it kindles. Likewise, the word of God devours, consumes or burns up what it is spoken against. As such, when God say, “I sent My word and healed them, and delivered them from their destruction” (Psalms 107:20), He is saying: “I sent My FIRE and healed them, and delivered them from their destruction.” Again, when Scripture declares: “…He cast out the spirits with a word, and healed all who were sick” (Matt. 8:16), it is saying that Jesus cast out the evil spirits in the possessed people with His word, and healed all who were sick (most likely by His word too).
By nature therefore, the word of God, like God Himself, is a consuming fire, and when it heals and delivers, it does so by its fiery attribute. The word of God heals us of sicknesses, diseases and infirmities by devouring, consuming or burning these enemies like fire does to firewood. It also delivers us from Satan and his evil spirits by devouring, consuming or burning these demons like fire does to firewood. Hallelujah!
As we read in Jeremiah 5:14, God will turn His words that we speak out into fire, and our enemies into a combustible material like firewood; apparently to judge and consume these enemies. God will also turn His words that abide inside of us into fire (Jer. 29:23), so that when we speak it, it comes out as fire. Do not consider these enemies to be humans. Rather, regard them as the sicknesses, diseases, infirmities and evil spirits mentioned above because, like enemies, they come to weaken, disable or kill us.
God can turn His word into fire for us through special favor as in the old covenant. But in the new covenant, you can cause this fire if the fire anointing of the Holy Spirit is strong on you. Always pray the Lord to fill you with greater and greater measure of His Holy Spirit, for the more of Him His Spirit you are filled with, the greater the intensity of that fire in you. As such, when you speak out the word of God against enemies attacking those you are praying for or ministering to, the word will go out as fire to consume the enemies in them. Also, when the word of God becomes fire inside of you, it will burn up sicknesses, diseases, infirmities and evil spirits in you if you properly direct it to these targets through focused warfare prayers. For all these reasons, divine healing are often associated by warm sensations to signal the fire of God at work.