As the stock market rose sharply on Thursday, CNBC's Jim Cramer pinpointed a key component of the bull case that helped equities climb: the lack of "explosive" Trump tweets.

"We didn't see a threat to Russia," the "Mad Money" host said. "We didn't get a tweet about an attack on the FBI or special prosecutor Robert Mueller, other than a riposte against the New York Times about what the president called fake reporting."

"If I wanted to fire Robert Mueller in December, as reported by the Failing New York Times, I would have fired him. Just more Fake News from a biased newspaper!" Trump wrote.

While Trump's silence on Russia doesn't necessarily mean that the White House won't retaliate against Russia, which may have supported the Syrian regime in a recent chemical attack, stocks certainly benefited from his relatively calm Twitter feed, Cramer said.

In an aside, Cramer labeled Amazon "the best stock to own when the president doesn't tweet" thanks to its 1.5 percent jump on Thursday.

"The absence of fiery tweets is a real positive now for the stock market," he said, adding that Trump's comments about progressing trade talks contributed to the strength.

Reports that the president would consider re-entering the Trans-Pacific Partnership and reigniting multi-lateral trade talks also gave stocks a late-day boost, Cramer said.

"Anything that makes it seem like Trump is not a total protectionist is considered good for worldwide commerce," he explained. "Even the whiff of a possibility of trade cooperation with anyone was enough to send the industrials flying."

Until recently, when U.S.-China tensions seemed to abate, industrial stocks had been under pressure because of the potential for more tariffs on top of the restrictions on steel and aluminum imports.

But on Thursday, the industrials, led by the stocks of Boeing and Caterpillar, roared for the first time since Trump announced the steel and aluminum tariffs.

"A reversion to 2017? Sure felt like it," Cramer said. "If we know one thing about 2018, it's that this market can't really get a full head of steam going without running into contrary data points. That said, days like today are a powerful reminder that good things can still happen and you need to stay the course."