During Monday's episode of "American Idol," Carrie Underwood shared a heartfelt testimony after contestants went head-to-head during a performance of Brandon Lake's "Gratitude."

One of the performances during Monday night's "American Idol" episode struck a nerve with Carrie Underwood, who held back her tears as she reflected on being openly Christian. After contestants Breanna Nix and Rylie O’Neill performed a cover of Christian worship singer Brandon Lake's song "Gratitude,

Carrie Underwood won "American Idol's" fourth season at 21 years old. Look back on what her career has looked like since she left Muskogee, Oklahoma.