Al-Kahf 18:19 وكذالك بعثناهم ليتساءلوا بينهم قال قايل منهم كم لبثتم قالوا لبثنا يوما او بعض يوم قالوا ربكم اعلم بما لبثتم فابعثوا احدكم بورقكم هاذه الى المدينة فلينظر ايها ازكى طعاما فلياتكم برزق منه وليتلطف ولا يشعرن بكم احدا ١٩

Such (being their state), we raised them up (from sleep), that they might question each other. Said one of them, "How long have ye stayed (here)?" They said, "We have stayed (perhaps) a day, or part of a day." (At length) they (all) said, "Allah (alone) knows best how long ye have stayed here.... Now send ye then one of you with this money of yours to the town: let him find out which is the best food (to be had) and bring some to you, that (ye may) satisfy your hunger therewith: And let him behave with care and courtesy, and let him not inform any one about you.