Our transgression can be erased. This, Rav Luzzato writes, is G-d's mercy in action. Said Resh Lakish, this means he regretted his former good deeds. From this passage, it appears that a person's regret for his good deeds has the ability to uproot and destroy the good deeds that he did. The execution of each commandment carries with it a spiritual effect.
Different commandments effect different areas of our spirituality in a positive fashion.
Because of the spiritual benefits that are part and parcel of obeying the commendments, it is worthwhile for an individual to perform these commandments even if not obligated to do so. It is for this reason that our forefathers Avraham, Yitzchak and Yaakov kept the commandments found in the Torah, even though they had not yet received the commandments. They appreciated the growth in spirituality that came with the performance of each Mitzvah, and therefore obeyed the dictates found in the Torah. However, there is another and more basic aspect to the commandments. They are, simply put, commandments.