Sorrow draws comfort that never would have come in joy.
For the rough roads there are iron shoes.
There is yet another suggestion in this old-time promise.

The divine blessing for every experience is folded up in the experience itself, and will not be received in advance.

The iron shoes would not be given until the rough roads were reached.

There was no need for them until then, and besides, the iron to make them was treasured in the rugged hills and could not be gotten until the hills were reached.
A great many people worry about the future.

They vex themselves by anxious questioning as to how they are going to get through certain anticipated experiences.