Quoting John G. Lake:

“You may be healed like a sunburst of God today, and tomorrow. The next week or the next month when you want healing, you may have to take it on the slow process. The action of God is not always the same because the conditions are not always the same. In the life of Jesus, people were instantly healed. I believe Jesus has such a supreme measure of the Spirit that when He put His hands on a man, he was filled  and submerged in the Holy Ghost, and the diseases withered out and vanished. But, beloved, you and I use the measure of the Spirit that we possess. [You can, as a member of His body, possess the Spirit in the same measure as He. God does not expect us to fulfill John 14:12 with less equipment than He had. W.H. Reidt] And if we have not got as much of God as Jesus had, then you pray for a man today, and you get a certain measure of healing, but he is not entirely well. The only  thing to do is pray for him tomorrow, and let him get some more, and keep on until he is well. That is where people blunder. They will pray for a day or two, and then they quit. You pray and keep on day by day and ministering to your sick until they are well.”

When John G. Lake ran the Healing Rooms in Spokane Washington (1915-1920, healings became so normal there that Spokane became the healthiest city in the world.