THE REAL CHALLENGE!
In this week's parsha, Hashem gives us a detailed warning on what will happen to us if we fail to follow the Torah properly. Following these gruesome details, the Torah goes on to discuss the rules of valuations. If somebody wanted to 'donate himself' to the Beis Hamikdash, the Cohanim would evaluate the person and state a monetary amount which he would then pay.
Rav Feinstein questioned why these two subjects are right next to each other? What does tochacha (reproof) have to do with valuations?
He answers that it's only after a person goes through trying times, which is most often a reproof from Hashem, that he can truly look at himself afterwards and give an honest evaluation.
Before any hard times, it's easy for a person to fool himself into thinking he's on a high spiritual level. But the truth is, a person can be judged properly when he sees how he holds himself in trying times. I believe it was Col. Joshua Lawrence Chamberlain of the famed 20th Maine (at least famed for us Civil War history nerds) that said, "War is for the participants a test of character: it makes bad men worse and good men better".
The war with the yetzer horah is no different. When it's peaceful, you can trick yourself, but in the heat of battle, you're able to take a good look at yousrelf and see who you truly are.