The main story in Parashat Shelach is the story of the
מרגלים or spies that Moses sends to tour the land of Canaan. Chazal say that this story is the greatest tragedy that happened to the Children of Israel in the desert, even greater than the sin of the Golden Calf.
The Parsha begins with G-ds commandment to Moses to send the spies, as it is written:
שלח לך אנשים ויתרו את ארץ כנען...
Send for yourself men, that they may spy out the land of Canaan... (13:2).
Rashi explains why this Parsha is presented after the previous episode of Miriams speaking about Moses to Aaron in order to show us that the spies saw that she was punished for speaking badly about her brother and they did not learn from her punishment.
Moses sends twelve spies from the desert of Paran, each the head of a tribe of Israel. Moses gives the men specific instructions. He tells them:
See what the land is and the nation that lives on it; whether they are strong or weak, if they are few or many. And how is the land in which they live, is it good or bad? And how are the cities in which they live, are they open or are they fortified? And how is the land; is it fertile or is it poor, does it have trees, or not? Strengthen yourselves and take some fruit of the land(13: 18-20).
The men return after touring the land for forty days and report to Moses, Aaron and to the entire congregation. They report that although the land indeed flows with milk and honey and this is its fruit...
the nation that lives there is mighty and the cities are greatly fortified... (13: 28).
They tell the people that they will not be able to go up against the nation
for they are more powerful than we are (13: 31) and that they also saw giants,
and we were like grasshoppers in their eyes (13:33). Of the twelve spies, Caleb and Joshua do not participate in the negative report.
When the Children of Israel hear the report of the spies, the people raise their voices and cry that night. (The Midrash says that that night was the 9th of Av, the date of the future destructions of the first and second temples. G-d told the Children of Israel that because they cried for no reason now, G-d will give them a reason to cry in the future.) The people even say to one another
let us appoint a leader and return to Egypt (14:4).
Moses asks G-d to forgive the people and G-d says
I have forgiven them (14:20). However, G-d says because they tested Him so many times, they will spend forty years in the desert, corresponding to the forty days that the spies spent touring the land of Israel. Except for Caleb and Joshua, the entire generation, from age 20 and up, will die in the desert and will not enter the Promised Land .
The Parsha also discusses the sacrifices that the Children of Israel will bring when they enter the land and mentions the mitzvah of separating a portion of the dough when making bread.
The Parsha ends with the commandment of tzizit, as it is written,
...ועשו להם ציצית על כנפי בגדיהם לדרתם...ולא תתורו אחרי לבבכם ואחרי עיניכם אשר אתם זנים אחריהם. (טו:לח-לט
...To make for themselves tzizit on the corners of their garments, throughout their generations...and you will not seek after your own hearts and your own eyes, which you go astray (15:38-39).
Rashi notes that the commandment And you will not seek after your own hearts is similar to the wording used from spying the land (13:25). The heart and the eyes are the spies of the body: the eye sees, the heart covets, and the body does the sin.