The end justifies the means.
He is afraid of his own shadow.
Upon a slight pretext the wolf takes the sheep.
Bought friends are not friends indeed.
Princes keep good reckoning, they never lose anything.
Neither reprove nor flatter thy wife, where any one heareth or seeth it.
He who visits you personally is better than another who sends a delegate.
Better ride on an ass that carries me than a horse that throws me.
Exert effort, you shall be rewarded.