They were wanting to know if He could give them that kind of sign. The interesting thing here is that the Jews expected what they called a ‘treasury of manna’ to be actually descending upon them.
When everything else is stripped away, once you came to Christ you admitted that everything else was bankrupt. When you admit that, even though you don’t feel you can understand Him or things are falling apart, you realize you have no other place to go.
As this text concludes then we see that the rejection was one where they overlooked the claims of this One who is right before them. It’s so easy for this to happen.
So Jesus then uses the Law of Moses to actually refute His accusers. In other words, they’re saying- we know where He comes from- Jesus of Nazareth- we know. The assumption was that when the Messiah comes He will come surprisingly and we won’t know whom He is.
Now the feast of the Jews, the Feast of Booths, was near. Therefore His brothers said to Him, Leave here and go into Judea, so that Your disciples also may see Your works which You are doing.