And thus did We rouse them that they might question each other. A speaker among them said: How long have you tarried? They said: We have tarried for a day or a part of a day. (Others) said: Your Lord knows best how long you have tarried. Now send one of you with this silver (coin) of yours to the city, then let him see which of them has purest food, so let him bring you provision from it, and let him behave with gentleness, and by no means make your case known to any one:

O my son! surely if it is the very weight of the grain of a mustard-seed, even though it is in (the heart of) rock, or (high above) in the heaven or (deep down) in the earth, Allah will bring it (to light); surely Allah is Knower of subtleties, Aware;