WASHINGTON--President Obama read Psalm 46 at the New York ceremony Sunday marking the tenth anniversary of the 9-11 attacks.

Principal deputy press secretary Josh Earnest explained why Obama selected that psalm.

"The President chose a scripture which he believed was most appropriate -- he believed it was particularly appropriate to use -- to read scripture this morning. And he chose a passage that talks of persevering through very difficult challenges and emerging from those challenges stronger," Earnest said.