He said something like...we are on the knife's edge, this is no hyperbole, we need to lock him up. The crowd clapped. He went on, and said some other stuff.
Here, I found a link. Even some Democrats freaked out about this. From the link:
Axios national political correspondent Alex Thompson claimed that a former Biden admin official, noting this could be politically unhelpful to Vice President Kamala Harris, texted him, "we gotta lock Joe up."
[A] current Biden admin official allegedly told the reporter, "For better or worse, no one is listening to him anymore and his words have little power and less reach. It’s a blip. Gone in any meaningful way by mid-day tomorrow if it makes it that long."
Link: https://www.msn.com/en-us/news/politics/commentators-insiders-deride-biden-calling-to-politically-lock-trump-up-no-cleanup-that-is-possible/ar-AA1sM2cz