Jesus conquered death by the resurrection. God raised Him up from the dead by the power of the Spirit:

"But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ from the dead will also give life to your mortal bodies through His Spirit who dwells in you."

Romans 8:11

The truth of Jesus' death and resurrection is a power that can help "give life to" our mortal bodies. It means healing for those who are sick and continuous healing so that we can be kept from becoming ill. 

After six hours on the cross, Jesus cried out: 

"It is finished!"

John 19:30

This means that all of mankind's sins and diseases have been totally defeated. The word "finished" in Greek means "paid in full" – not in part, but fully and completely! Full salvation and complete healing. 

The resurrection is God's "receipt" that all people can be forgiven, saved, and healed. If there had been one sin or disease that Jesus had not paid for, His death would have been a failure. Jesus' death and resurrection is the gospel in a nutshell. 

Paul says: 

"Moreover, brethren, I declare to you the gospel which I preached to you, which also you received and in which you stand; by which also you are saved, if you hold fast that word which I preached to you—unless you believed in vain. For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures, and that He was buried, and that He rose again the third day according to the Scriptures."

1 Corinthians 15:1–4

All of God's blessings radiate from an empty cross and an empty tomb. Therefore, Paul says:

"For I am not ashamed of the gospel of Christ, for it is the power of God to salvation for everyone who believes, for the Jew first and also for the Greek."

Romans 1:16

It is "the power of God to salvation" in its entirety, covering both salvation and health.

God has entrusted us with the gospel. It is incredibly great. Indescribable!