“We have to raise the bar (about security). This is the challenge.”

“The challenges are significant, but we believe we're making progress.”

“I want you to be confident that you can challenge.”

“We are challenging the philosophy of scientific materialism, not science itself,”

“It's now a bigger challenge for companies to retain their employees.”

“There is nothing like a challenge to bring out the best in man.”

“how depression challenged a president and fueled his greatness.”

“Combining academic work with raising a family is a big challenge.”

“Legal challenges are not uncommon, and we work through those.”

“It certainly raises the bar as far as the challenge before us,”