Who said "A man who cannot command himself cannot command others."?

This quote is attributed to Stannis Baratheon.

A man who cannot command himself cannot command others. - Stannis Baratheon

"A man who cannot command himself cannot command others."

Stannis Baratheon Leadership

"Duty is the death of love."

"I am of the night."

"The night is dark and full of terrors."

"A king does not ask, he commands."

"A leader must be fair and just."

"Integrity is everything."

"One must take responsibility for one's environment."

"In this house, I make the decisions"