The U.S. Supreme Court issued stays of execution Wednesday for three Oklahoma death-row inmates whose challenge to the state's lethal-injection formula will be heard in the spring, NBC News reported. One prisoner, Richard Glossip, had been schedule to die Thursday night. His cause has been championed by prominent capital-punishment opponent Sister Helen Prejean, who on Tuesday called for a repeal of the death penalty in the state. "There is no humane way to kill a conscious, imaginative human being," Prejean said. "We the citizens have our name on that gurney." The high court has agreed to hear a challenge to the legality of lethal injection for the first time since 2008. The Oklahoma case centers on the first of three drugs administered to a condemned inmate — the sedative midazolam, which opponents say isn't strong enough to protect a prisoner from the other two chemicals used.