Watch Barack Obama sing Amazing Grace at Charleston pastor's funeral

Barack Obama broke into a rendition of Amazing Grace as he concluded his eulogy at the funeral of Clementa Pinckney in Charleston on Friday.

The US president spoke at length about the "grace" of Pinckney, a church leader and member of the South Carolina senate, as well as the other eight members of a bible study group who were gunned down last week.

Mr Obama then lowered his head to the microphone and slowly began to sing the hymn. As his words echoed around the TD sports arena, the funeral's organist and all others in attendance joined in with him.

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