The most highly-polished person may be thoroughly depraved in heart; and his superfine manners may, after all, only consist in pleasing gestures and in fine phrases.
On the other hand, it must be acknowledged that some of the richest and most generous natures have been wanting in the graces of courtesy and politeness.

As a rough rind sometimes covers the sweetest fruit, so a rough exterior often conceals a kindly and hearty nature.

The blunt man may seem even rude in manner, and yet, at heart, be honest, kind, and gentle.
John Knox and Martin Luther were by no means distinguished for their urbanity.

They had work to do which needed strong and determined rather than well-mannered men.

Indeed, they were both thought to be unnecessarily harsh and violent in their manner.