Presumptive Republican nominee Donald Trump responded to President Obama’s jab during a commencement speech last weekend at Rutgers University.

Taking to Twitter, Trump posted:

"In politics, and in life, ignorance is not a virtue." This is a primary reason that President Obama is the worst president in U.S. history! — Donald J. Trump (@realDonaldTrump) May 17, 2016

Without calling Trump out by name, Obama focused on the Republican nominee throughout the graduation speech.

“In politics and in life, ignorance is not a virtue,” Obama told the graduates. “It’s not cool to not know what you’re talking about. That’s not keeping it real or telling it like it is. That’s not challenging political correctness. That’s just not knowing what you’re talking about. And yet we’ve become confused about this.”

“I guess it’s part of human nature — especially in times of change and uncertainty — to want to look backwards and long for some imaginary past when everything worked, and the economy hummed, and all politicians were wise, and every child was well-mannered, and America pretty much did whatever it wanted around the world,” Obama also stated. “Guess what? It ain’t so. The good old days weren’t all that good.”

He also criticized Trump’s proposed temporary ban on Muslim immigration into the United States until a proper vetting process was instituted.

“Isolating or disparaging Muslims, suggesting that they should be treated differently when it comes to entering this country, that is not just a betrayal of our values. That’s not just a betrayal of who we are — it would alienate the very communities at home and abroad who are our most important partners in the fight against extremism,” Obama challenged.

According to CNN, Obama’s criticisms were similar to previous jabs he’s taken toward Trump without naming the real estate mogul.