(13:2) Send for yourself men to scout the Land of Cannan which I am giving to the children of Yisrael, of every tribe of their fathers shall you send a man, everyone of them a leader among them.

Rashi comments here: Why is the section dealing with the incident of the spies juxtaposed to the section dealing with the incident with Miriam? He answers that it is to teach us that although she had been punished for speaking negatively about her brother, and the spies had seen this, yet they had not learned from it. The sefer Sifsei Chachomim asks on Rashi: Perhaps these two events happened one after the other, (and thus there was no problem to begin with that needed to be answered)!

But it seems to me that we can answer for Rashi from that which is written in the Yalkut Reuveini: “And they (the spies) returned from scouting the land” – when the spies came and saw that Yisrael were learning the laws of Challah, they said to them: You are not going to enter Eretz Yisrael, yet you are learning the laws of Challah! (The laws of Challah did not apply to them until they entered the Eretz Yisrael).

And it also says there: From where did Yisrael obtain wine for the wine libations in the wilderness for forty years? Rabbi Levi answered that they obtained it from the bunch of grapes that the spies had brought back.

And incidentally, with this midrash we can explain what prompted the spies to take a bunch of grapes so much larger than the fig and the pomegranate – the grapes were carried by eight men, whereas the fig and the pomgranate were carried by only two. From this midrash we see that their intention was in order that Yisrael should have enough wine to last for many years, since thay did not want to enter Eretz Yisrael.

What emerges from all this is that the sections dealing with the laws of Challah and the laws of the wine libations were taught to them before the incident of the spies, and if so, Rashi is well justified in asking why the section dealing with the spies is juxtaposed to the section dealing with Miriam – the Torah should have instead written the sections dealing with the laws of Challah and the wine libations before the section dealing with the spies.