The Rev. Clementa Pinckney described as "irreplaceable"

As mourners in Charleston looked back on the life of the Rev. Clementa Pinckney, "service" was a word often used to describe how he lived, reports "CBS This Morning" co-host Gayle King.

When not serving the Emanuel AME congregation, Pinckney, also a state senator, served his South Carolina constituency.

He spoke about his goals as a leader with Henry Louis Gates Jr. for PBS in 2012.

"We have a legacy to uphold: the people who died so that we could have the right to vote; the people who sacrificed so that we would one day realize the dream of a black president," he said.

History was integral to his life's work -- embracing it from his revered church while working to change history's course through legislation.

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After Walter Scott, an unarmed black man, was gunned down by a North Charleston police office in April, Pinckney pushed for more visible justice by renewing his call for the use of police body cameras.

"It is my hope that as South Carolina senators, that we will stand up for what is best and good about our state," he said.

Pinckney's cousin, Armstrong Williams, remembers the state senator as a man determined to make a difference in government, but being most effective through his pulpit.

"He always found himself back at that church. That's where he could have the greatest impact with young people," Williams said.

In 2013, Pinckney spoke about the relevance of duty and pursuit of values -- no matter the cost.

"Could we not argue that America is about freedom, whether we live it out or not, but it really is about freedom, equality and the pursuit of happiness. And that's what church is all about," he said.

With his church now a crime scene, Pinckney's state senate desk became a temporary memorial, cloaked in black and topped with a red rose. It is a tribute from the faithful to a man who ultimately gave his life for the community he served.

"People trusted him they respected him and you know he's just irreplaceable, irreplaceable," Williams said.