"Healing is not something provided for in the Atonement." That is the claim made by many, usually by folks who have not actually witnessed or received any bona fide healing. Although, some who have still do think healing is not provided for in the atonement. But let's examine the question a little further.
Atonement. What is meant by "the Atonement"? Obviously, the suffering and death of the Lord Jesus is meant. While it is true that "atonement" can be used in a technical sense regarding the remission and removal of sins, and thus is distinct from "passover" which is more redemptive in outlook and signification, yet I do not think that folks are splitting the death of Christ into it's component parts and effects and saying "healing is not in THAT compartment of His Passion..."! So, let us presume to use "the Atonement" in it's generally accepted and wide sense as referring to the suffering and death of Christ.
Another term that refers to His suffering and death is "the Cross". When someone says we are "saved by the cross" they do not mean they are saved by the actual wooden torture and execution implement common to Imperial Rome. They mean the suffering and death of Christ, who suffered, and eventually died on such a cross. The term "cross" is thus what is known as a metonymy, a figure of speech where a part represents the whole. We speak of the suffering and death of Christ as "the cross" because that is where He expired - on a cross. It is just like if a person speaks of "the Pentagon" to refer to the entire military establishment or the leadership thereof. Or, as when a person refers to "the Crown" to refer to the entirety of a monarchical government and it's administration. Just so, "the cross" is used to refer to the entirety of Christ's suffering and death. And, "the preaching of the cross" is a phrase that means the preaching of Jesus Christ
as it relates to His suffering and death.
Now, watch this:
1 Corinthians 1:18 KJV For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God.
Do you see that? The preaching of the cross (Christ's suffering and death) is THE POWER OF GOD to us who are saved. Meaning, we are saved by the power of God - how else could we be saved? - and this power of God is made known to us by the preaching of the suffering and death of Christ. This means we are told about Christ's suffering and death, and believing that message, we are saved. Thus it is the suffering and death of Christ which effects salvation, through us hearing about it and believing in it.
Now, who will claim that healing does not occur by the power of God? Healing is an effect of the power of God, how could it be otherwise?
Luke 9:42-43 KJV ...And Jesus rebuked the unclean spirit, and healed the child, and delivered him again to his father. (43) And they were all amazed at the mighty power of God...
Healing, deliverance, and salvation are effected by "the power of God". And proclaiming the suffering and death of Christ is what makes the power of God available to people. This is why Jesus said the following:
Mark 16:15-18 KJV And he said unto them, Go ye into all the world, and preach the gospel to every creature. (16) He that believeth and is baptized shall be saved; but he that believeth not shall be damned. (17) And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; (18) They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.
We are to preach the gospel - the good news which concerns the suffering and death (and resurrection!) of Jesus Christ. When people hear and believe this message, not only do salvations result, but so do healings and other mighty works of power (miracles). Why? Because it is connected to the gospel, which is centered on the suffering and death - and yes, the resurrection - of Jesus Christ. It is that suffering and death of Messiah which secures the wonderful results of salvation, miracles, and healings. And it is the Lord's resurrection from the dead which verifies the efficacy and effectualness of His suffering and death. Amen!
So then healing most certainly is made available to us via the suffering and death of Christ. Preaching the cross of Christ is the power of God, that is, it informs people of what they should expect as a result of Christ's suffering and death and resurrection. And that includes healing.
Matthew 8:16-17 KJV When the even was come, they brought unto him many that were possessed with devils: and he cast out the spirits with his word, and healed all that were sick: (17) That it might be fulfilled which was spoken by Esaias the prophet, saying, Himself took our infirmities, and bare our sicknesses.
Where did Isaiah say that?
Isaiah 53:4-5 KJV Surely he hath borne our griefs, and carried our sorrows: yet we did esteem him stricken, smitten of God, and afflicted. (5) But he was wounded for our transgressions, he was bruised for our iniquities: the chastisement of our peace was upon him; and with his stripes we are healed.
Apparently, the apostle Matthew understood this prophecy concerning Messiah to be fulfilled in Christ healing people. The prophecy concerns Messiah's suffering and death, yet Matthew says it finds fulfillment in Christ healing the physically sick! The connection between the suffering and death of Christ - "the Atonement" - and physical healing by the supernatural power of God, is clearly and unambiguously made by the apostle.
We are to believe on Jesus according to the word or teaching of the apostles. That requires us to believe that Christ healing the sick
is a fulfillment of the prophecy concerning His vicarious suffering and death on our behalf. And thus, healing is definitely in the Atonement. Praise Jesus!