Al-An'am 6:28

Bal bada lahum ma kanooyukhfoona min qablu walaw ruddoo laAAadoo limanuhoo AAanhu wa-innahum lakathiboon

But what they concealed before has [now] appeared to them. And even if they were returned, they would return to that which they were forbidden; and indeed, they are liars.

In fact, what they were concealing earlier will become clear to them. If they were sent back, they would again go for what they were forbidden from, as they are sheer liars.