"Preachers all over the country, shaking off their resume," he told his congregants in 2015, when he was considering a challenge to U.S. Sen. Johnny Isakson. "Tell them to hold on to it. We've had five pastors since 1886, and I plan on keeping up the tradition."
It would still be legal for Warnock to preach and run as a Democrat against Loeffler, a financial executive appointed last month to fill Isakson’s seat after he retired for health reasons. The victor of the November election will serve the remaining two years on Isakson’s term.
But Warnock would have to steer clear of overtly politicking on the pulpit and using church resources for his campaign. The church could not endorse Warnock or collect cash for him. Any political activity such as forums or get-out-the-vote efforts must be done in a nonpartisan way.
Violating those rules would risk penalties from the Internal Revenue Service, which classifies churches as tax-exempt 501(c)(3) organizations that don't pay federal income tax but also can't actively engage in political campaigns.
More: DeKalb's top prosecutor will not run for US Senate in Georgia
More: Did Raphael Warnock just welcome Kelly Loeffler to a U.S. Senate fight?
More: AJC Poll: Georgia's new senator is playing catch-up with voters
Preachers often discuss hot-button issues such as voting rights and abortion from the pulpits, but they risk losing their tax-exempt status if they openly back candidates or pay for campaign activities.
His candidacy would also invite scrutiny from Republican trackers who will analyze his Sunday sermons in search of a legal slip-up. Tax analysts say even using a church email account for campaign business could trigger sanctions.
Warnock is said to have support from prominent state and national Democratic figures, including former Georgia gubernatorial contender Stacey Abrams, when he enters the race.
Within the last two weeks, several other potential candidates announced they wouldn't run, a sign that party powerbrokers are trying to clear the field for Warnock. Two other Democrats say they still plan to run: Matt Lieberman, an entrepreneur; and Ed Tarver, a former federal prosecutor.
Though Warnock has not commented on his Senate plans, back in 2015 he was ready in an interview with examples of pastors who have preached on Sundays and campaigned on Mondays.
He pointed to former New York U.S. Reps. Adam Clayton Powell Jr. and Floyd Flake; and ex-Pennsylvania U.S. Rep. Bill Gray – all black preachers who maintained a presence on the pulpit after they were elected.
“The question is, can I serve the people of Ebenezer and the people of Georgia as a servant at the same time?” he said to his congregation then. “Some people say you can’t. Some people say you can.”