Who said "The path of honor is often the most difficult."?

This quote is attributed to Lady Sif.

The path of honor is often the most difficult. - Lady Sif

"The path of honor is often the most difficult."

Lady Sif

"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."