Who said "I have learned that patience is its own form of power."?

This quote is attributed to Lady Sif.

I have learned that patience is its own form of power. - Lady Sif

"I have learned that patience is its own form of power."

Lady Sif Patience

"I am a warrior of Asgard, and I will not falter in the face of darkness."

"Strength is not measured by the power of one's blade, but by the resolve of one's heart."

"A true friend stands beside you, not behind you."

"We are forged in battle, but refined through compassion."

"Patience is a virtue I'm still learning."

"I may be a redhead, but I'm not a hothead."

"Patience is a virtue."

"Patience is a virtue I never learned."