2 Chronicles 7:14 (KJV)

"If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land."

I risk crossing over into non-secular territory, but the Casting Crowns song "Start Right Here" is one that seems particularly poignant, in my view, to recent times. I usually follow it with Melissa Helser's "Revival's In the Air".