And he said, Come. And when Peter was come down out of the ship, he walked on the water, to go to Jesus.
But when he saw the wind boisterous, he was afraid; and beginning to sink, he cried, saying, Lord, save me.

These things I have spoken unto you, that in me ye might have peace. In the world ye shall have tribulation: but be of good cheer; I have overcome the world.

COMMENTARY

But when he saw the wind boisterous, he was afraid; and began to sink
In the world ye shall have tribulation
Storms exist, they really do. Sometimes we make up pretend afflictions in our own heads, but even if we had the best of attitudes we still would have more than enough real troubles. Overcoming the world, therefore, is not simply a case of mind over matter.
Jesus, himself, attested that in this world we would have tribulation. It is unavoidable, because each of us is necessarily tied to a body that is subject to the world.

And when Peter was come down out of the ship, he walked on the water, to go to Jesus
And so we do not deny the presence of life’s storm, we only deny them power to control us. They might be able to affect the body, but we decide whether they gain access to the soul.
The storm was already raging when Peter stepped out into the water, but he overcame it by asserting that there was a higher power than it. Then he faltered and began to regard the storm more than his Savior. It was only then that the storm was able to claim him.

But be of good cheer; I have overcome the world
The problem with “mind over matter” is that it still tries to put the storm-defying power in us. I can clench my fists and grit my teeth and tell myself that I don’t feel the storm, but it won’t work. I’ll only exhaust myself and still be swept away. Have I overcome the world? No, only Christ has. Peter was not being sustained not by his mastery of the storm, only by Christ’s.
So forget about “mind over matter,” the correct mantra for overcoming our trials is “Christ over matter.”