President Obama Leads Charleston Crowd in Powerful Rendition of 'Amazing Grace'

— -- President Obama delivered one of the most emotional moments of his presidency when he led a crowd of 5,500 people in singing "Amazing Grace" at the funeral services today of the Rev. Clementa Pinckney.

Towards the end of a nearly 40-minute eulogy for Pinckney, the president spoke about the grace the slain pastor embodied and started repeating the words of the famous gospel hymn.

"If we can find that grace, anything is possible. If we can tap that grace, everything can change. Amazing grace. Amazing grace," he said.

The president then paused for 12 seconds before he began belting the words "Amazing Grace." Shortly after, the crowd of 5,500 people inside the TD Arena joined the president.

"Clementa Pinckney found that grace," the president said as the crowd sang. "Cynthia Hurd found that grace. Susie Jackson found that grace, Ethel Lance found that grace, DePayne Middleton-Doctor found that grace, Tywanza Sanders found that grace, Daniel L. Simmons Sr. found that grace, Shardona Coleman Singleton found that grace. Myra Thompson found that grace."

"Through the example of their lives, they've now passed it onto us," Obama added. "May we find ourselves worthy of that precious and extraordinary gift. As long as our lives endure, may grace now lead them home. May God continue to shed his grace on the United States of America."

The moment sparked immediate response on Twitter, with some comparing the president to a pastor.

ABC News' John Parkinson contributed to this report.