Robert Christy, comp. Proverbs, Maxims and Phrases of All Ages. 1887.

Difficult

Nothing is difficult to a willing mind.

Nothing so difficult but that man will accomplish it.Horace.

The difficult thing is to get foot in stirrup.

To the brave and faithful nothing is difficult.Latin.

What one knows not how to do is difficult, what one knows how to do is not.Chinese.