Quran 18:19

In time We woke them, and they began to question one another. One of them asked, ‘How long have you been here?’ and [some] answered, ‘A day or part of a day,’ but then [others] said, ‘Your Lord knows best how long you have been here. One of you go to the city with your silver coins, find out where the best food is there, and bring some back. But be careful not to let anyone know about you