Charles Spurgeon says in All of Grace":

“It would be a very wonderful thing if one could stand at the foot of the Niagara Falls, and could speak a word which should make the river Niagara begin to run up stream, and leap up that great precipice over which it now rolls in stupendous force. Nothing but the power of God could achieve that marvel; but that would be more than a fit parallel to what would take place if the course of your nature were altogether reversed.”

We easily and often forget that sanctification is not our duty. In fact, we don’t really have the capacity to change our hearts at all—the necessary condition of real sanctification. Rather, it’s God’s work in the Holy Spirit.

No more could someone stand at the foot of the Niagara Falls and will the water to go back up, could a man stand in a mirror and will himself into a sanctified state.

I suppose in most ways, that’s a pretty encouraging reminder.