“You are all standing here today, all of you, before Hashem, your G-d, the heads of your tribes, your elders, and your officers- all the men of Yisroel; your small children, your women and your convert who is in the middle of your camp, from the hewer of your wood to the drawer of your water, for you to pass into a covenant of Hashem, your G-d and into His oath that Hashem our God made with you today” (Devorim 29/9-11)
Rashi (possuk 12) quotes a Medrash that when Bnei Yisroel heard the one hundred minus two (ninety eight) curses in last week's parsha in addition to the forty nine in Torahs Kohanim (sefer Vayikra- specifically in Parshas Bechukosai) their faces turned white from fright! They said, "How can we survive such punishment?" Moshe consoled them and said, "You are all standing here today! Even though you have done things to anger Hashem, Hashem did not annihilate you and you still exist."
Zera Shimshon asks two questions. Firstly, why were they only frightened after hearing the curses in last week's parsha, Ki Savoh, and not after they heard the ones in Bechukosai? Those curses are also pretty scary.
Secondly, why were they comforted when Moshe told them that they were not destroyed? Maybe the reason for this was that they did not yet make a covenant with Hashem to keep His mitzvos? However, now that they made a covenant to keep the mitzvos there is good reason to be scared.
Zera Shimshon answers that a curse or promise written in the Torah does not have to be fulfilled according to the dry literal meaning of that possuk. As long as a description of what happened fits into the words of the possuk it is considered that the possuk is fulfilled.
For instance, it was written in last week's parsha, "Cursed is the one who causes a blind person to go astray on the road", which according to the strict interpretation this curse only applies to a person who gives wrong directions to a blind person. Rashi however comments that also included in this curse is someone who gives bad and malicious advice to someone who is "blind" to the proper course of action to take.
Yaakov Avinu was very concerned that this curse would be fulfilled in him if he would trick Yitzchak to think that he was Eisav. The only reason Yaakov Avinu agreed to go with Rivka's plan and fool Yitzchak was because Rivka promised him that if it was really bad advice she will accept on herself the curse.
We also find this same idea concerning dream interpretation, but in a situation when the curse was milder than the strict interpretation of the dream. The Gemara in Brochos (56A) relates that Bar Hediya, a person who interpreted dreams in the time of Abaya and Ravva, interpreted the exact same possuk two different ways depending if someone paid for his dream to be interpreted or not. For Ravva, who paid Ben Hediya, he interpreted it that something good will happen. However, for Abaya, who did not pay him, he interpreted it to mean that something bad would happen. We see from here, explains Zera Shimshon, a curse does not have to be fulfilled according to the literal interpretation of a possuk.
There are two curses in the curses of Ki Savoh that aren't written explicitly, "Also every sickness, and every plague, which is not written in this Torah, will Hashem bring upon you, until you will be destroyed. (Possuk 61)"
According to this, Zera Shimshon explains, when Bnei Yisroel heard the curses in Bechukosai they weren't tremendously scared. They knew that even though the curses sounded very scary, Hashem could bring these curses in a very gentle way, like a loving parent who must punish his child. The parent looks for the easiest punishment to give the child in which the lesson will still be learned.
However, when they heard the curses in Ki Savoh things were different. Since two of the curses were not specified, they reasoned that this is a sure sign that the rest of curses will be executed literally! They therefore "turned white from fright"!
Moshe comforted them by saying that according to the strict interpretation of the possuk (Shemos 22/19) "Someone who brings offerings to the gods shall be destroyed, only to Hashem alone", after the incident of the Golden Calf, Hashem should have annihilated the Jewish people. The reason Hashem didn't was because Hashem promised our forefathers, Avraham, Yitzchak, and Yaakov that Hashem will not exchange us for another nation. Therefore, the promise to our forefathers is still active and therefore just like the end of the possuk, "Also every sickness, and every plague, which is not written in this Torah, will Hashem bring upon you, until you will be destroyed" Hashem will not literally destroy Bnei Yisroel as we see that they were not destroyed after the sin of the Golden Calf, so there is no need to be frightened that the other curses will be executed literally.
The Zera Shimshon adds that according to this we can understand an interesting difficulty in the above words of Rashi. Rashi writes, "When Bnei Yisroel heard the one hundred minus two curses in last week's parsha in addition to the forty nine in Torahs Kohanim their faces turned white from fright!" Why did Rashi write one hundred minus two instead of ninety eight like he wrote forty nine and not fifty minus one?
According to the above, Rashi's wording is exact. It was the "minus two" curses, the ones that weren't explicitly written that caused them to be so worried!