I saw Beck on CNN laughing off the incident on his radio show. He said he was actually threatening to stab his co-host, not Trump, yuk yuk yuk. He said that he got it all straightened out with the Secret Service, yuk yuk yuk. Then went on to insult Trump supporters who are the real culprits in the event, because they accused him of threatening to stab Trump.
I listened to the audio of his radio show several times, and it does sound like he said that he would stab Trump, and that the stabbing wouldn’t stop. But, it does sound like the Secret Service did talk to him, and he managed to convince him that he was yoking it up over stabbing his co-host.
There's a reason Rush doesn't endorse candidates. He doesn't want to alienate a huge portion of his audience.
Beck has been unlistenable for months, and very insulting to anybody not supporting Cruz.