>>11258193 lb
It wasn’t in a speech. It’s anecdotal at best, but might not have been said at all, except perhaps in private to Bobby. The NYT reported it at some point, claiming it was said to one of the JFK admin’s highest officials, but that may just be mis/disinfo. Like many supposed quotations that do the rounds, it has no solid attestation or attribution. Sounds plausible, but nothing to hang your hat on.