Here are the key points from what he said and what they mean:

Communist Party is in charge and ‘totally correct’

Mr. Xi’s speech stood out for his defense of the Communist Party as the designer and guardian of China’s prosperity and stability.

He has often made that case, and when his predecessors, Jiang Zemin and Hu Jintao, spoke on the 20th and 30th anniversaries of the 1978 shift, they also gave plenty of space to praising the party. Even so, Mr. Xi’s comments seemed strikingly prominent, especially when many investors had hoped for a more moderate message.

Summarizing what he described as the lessons from China’s past four decades, Mr. Xi said, “First, the party’s leadership over all tasks must be adhered to, and the party’s leadership must be incessantly strengthened and improved.”

If anyone watching still expected that Mr. Xi would seek to moderate his hard-line reputation and reveal himself to be a political liberalizer, he used this meeting to send an emphatic “no.” The party’s socialist path, doctrine and policies over the past 40 years, he said, had all been “totally correct.”

An olive branch in a budding Cold War

Mr. Xi referred only obliquely to the elephant in the room: the trade war with the United States and the strain that deteriorating relations has put on China’s economy.