In Parshas Nitzavim (Devarim 30:15) we are presented with two options. We can choose to be good and thereby live or we can be bad which will bring death. The options that are given in Parshas Nitzavim resemble the choices given in Parshas Re'eh (Devarim 11: 26-28), but they differ in one respect. Though both Parshios present the choice between good and bad, the ramifications of our actions in each case are different. In Parshas Re'eh, the path of good is described as a blessing, whereas the path of evil is a curse. In Parshas Nitzavim, good is synonymous with life itself, whereas evil does not bring a mere curse, but rather death. Why are the consequences of one's choices so much more severe in Parshas Nitzavim than in Parshas Re'eh?
Immediately prior to the choices delineated in Parshas Nitzavim the mitzva of teshuva is given. Although teshuva is a wonderful gift, it carries with it an immense responsibility. One who fails to take advantage of the opportunity to do teshuva commits a terrible sin by not appreciating the significance of this gift from Hashem. Prior to the introduction of teshuva, a life devoid of Torah was merely a cursed existence. Now that teshuva can be performed, if one still refuses to do so, actions are not only cursed but are synonymous with death.
It is this awesome responsibility that accompanies teshuva that explains a difficult statement of the Rambam in Hilchis Teshuva. On Rosh Hashanah it is determined whether a person is righteous, wicked, or in the middle. A person is considered righteous if he has even one more merit than sin to his credit, and wicked if his sins out number his merits. Those whose merits and sins are equal are given that opportunity to repent between Rosh Hashanah and Yom Kippur. The Rambam writes that one who does not repent at this time is automatically determined to be wicked. Why should the lack of repentance necessarily seal the person's fate? Perhaps he performed other mitzvos between Rosh Hashanah and Yom Kippur that could tip the balance in his favor? Apparently the Rambam understands that the sin of not doing teshuva is of such magnitude, particularly at a time such as the Aseres Yemei Teshuva when teshuva is presented as a gift, that no merit can offset the consequences.
As we approach the period of time dedicated to teshuva, let us remember that teshuva is not only a gift, but a responsibility. May we merit to appreciate this wonderful opportunity that is presented to us.