“Shelach Lecha” means “send out for yourself”, referring to the spies that Moshe will send into Canaan to do a little “reconnaissance” on the strategic strengths of the various peoples living in Canaan. When the spies let their fear get the better of them and bring back an evil report, Abba YHWH officially enacts punishment that they will spend an additional 40 years wandering in the wilderness, or a total of 42 years from the time they left Egypt. However Caleb and Joshua prove themselves to be the voices of righteousness and will not give into fear.
Then, for the second time, Abba YHWH offers to destroy all Israel and start over a new tribe with Moshe as leader and the fallout from this occasion is most interesting, to say the least. Chapter 15 though also follows the pattern of the previous cycle when Abba YHWH offered to start over with Moshe, Moshe refused, and the final verdict from Abba YHWH comes down. In both cases, Abba YHWH reassures Israel by re-issuing his Torah requirements, meaning that even for those who will die in the wilderness the tribes they are part of will live through obedience to Abba YHWH’s Word.