Judge Merchan told jurors that Michael Cohen is an "accomplice" to the alleged crime, so the jury cannot convict Trump on Cohen's testimony alone.

Even if they believe Michael Cohen, they need to rely on evidence corroborating his testimony, Merchan said.

Trump, at the defense table, appeared to perk up just a bit at this, looking up at Merchan as he delivered this information to the jury.

Judge Merchan told the jury that they have the ultimate authority in determining the truthfulness of a witness' testimony -- an instruction that might come in handy given the emphasis that defense lawyers placed on Michael Cohen's testimony, which they say includes lies.

"You will alone determine the truthfully and the accuracy of the testimony of each witness," Merchan said.

He added that the jury could either disregard the testimony of an untruthful witness entirely, or disregard part of it.

"There is no particular formula" to determine credibility, Merchan said.

"You may consider whether the witness has any interest in the outcome of the case," he said -- another matter that might weigh on jurors' minds.

"You may consider whether a witness did have, or did not have, a motive to lie," the judge said.

Trump's attorney had told the jury Cohen had an "axe to grind" against his former boss. Prosecutors partially conceded that Cohen had a motive, acknowledging that, to date, he is the only one who suffered any consequences from the matter at hand.

Trump, at the defense table, appeared to look over to the jury and offer a bit of a closed-mouth grin.

Judge Merchan instructed the jury that they cannot hold Trump's not testifying against him.

"Defendant is not required to prove that he is not guilty," he said.

"The defendant is not required to prove or disprove anything," said the judge.

Judge Merchan told the jury that they should not speculate about the sentence or punishment in the case.

"It will be my responsibility to impose an appropriate sentence," Merchan said.

The judge also had to advise the jury about this yesterday after defense lawyer Todd Blanche argued that the jury "cannot send somebody to prison" based on Michael Cohen's testimony.

The jury appears to be laser focused on Merchan during the charge. Half of the jurors appear to be taking notes.

While the jury deliberates, Trump -- from the courthouse -- posted to social media about the readback that the jury just heard.

During the readback, the jury heard former National Enquirer publisher testify about a June 2016 phone call he had with Trump after Playboy model Karen McDougal came forward with a story of a year-long affair with Trump, which Trump has steadfastly denied.

"This story about Karen, since she's claiming that she has a relationship with you, should be taken off the market," Pecker recounted telling Trump -- to which Trump replied, "I don't normally -- I don't buy stories because it always gets out."

"I still think you should buy the story," Pecker testified that he told Trump, to which Trump replied, "I'll speak to Michael, and he'll get back to you."

In his social media post, Trump said, "Testimony conclusively showed that I clearly stated, "I DON'T BUY STORIES!" -- Not that there would be anything wrong with doing that -- NDA's [nondisclosure agreements] are PERFECTLY LEGAL AND COMMON!"

Pecker testified that the National Enquirer eventually paid McDougal $150,000 to catch and kill her story so it would not become public, under the expectation that the money would be reimbursed by Trump -- although the reimbursement never materialized.

-Kelsey Walsh