This is one of these alleged Einstein quotes that not only is never sourced, but not even dated. It smells like nonsense. Einstein and Tesla had virtually zero interactions (the only thing on record is a pro-forma "happy birthday" note from Einstein to Tesla which was produced only because someone else asked him to write it, along with 70 other scientists and engineers), and Tesla spoke against Einstein's relativity theory in the harshest of terms (he essentially believed in the ether theory that Einstein's work discarded). It sounds like something the Internet Tesla cult has invented; in any event, many of them have uncritically latched onto it, as they have latched on to many myths.

The burden of proof here is on anyone claiming he said it; there is literally no evidence that Einstein said this and absolutely no reason to think he would.