Who said "Change is the only constant; adapt or be left behind."?

This quote is attributed to Lady Sif.

Change is the only constant; adapt or be left behind. - Lady Sif

"Change is the only constant; adapt or be left behind."

Lady Sif Change

"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."

"Change brings new opportunities."

"Every day is a new opportunity."

"Healing doesn't mean forgetting."

"You either get better or you get bitter."