Healing - Authority or Gift?

Is healing done on authority?

Then he called his twelve disciples together, and gave them power and authority over all devils, and to cure diseases.
- Luke 9:1 (KJV)

Or is it a gift?

To another faith by the same Spirit; to another the gifts of healing by the same Spirit.
- 1 Corinthians 12:9 (KJV)

I think that before the Holy Spirit (and the gifts) was given (after the ascension of Jesus into heaven) it would have had to be on authority. Note that Luke 9:1 was spoken to the disciples, and not to us.

Today we find that only those with the gift of healing can heal.

Have all the gifts of healing? do all speak with tongues? do all interpret?
- 1 Corinthians 12:30 (KJV)

I fully expect that in the last days many signs and wonders (including healing) will take place.

And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams.
- Acts 2:17 (KJV)