The passuk states “and you shall guard My decrees and My laws… וחי בהם and you shall live with them.” What does the Torah mean to teach with וחי בהם?
The Rashbam explains if a person does not fulfill the mitzvos he will receive the punishment of krisus. This is the opinion of Rebi Shimon who says that it states ונכרתו הנפשות העושות.. and it states אשר יעשה אותם האדם וחי בהם. Rashi explains (on the Gemara) that if one transgresses the mitzvos of forbidden relationships he will be cut off early. And if he fulfills these mitzvos by holding back and staying away, he will be given life. This means that one who fulfills mitzvos will receive reward here in this world. The Gemara however brings that Rebi Yaakov saw a son sent by his father to bring down birds from the top a tall building. He went up, and sent away the mother bird, and took the chicks. On the way back the son fell and died. Although the Torah guarantees the reward of למען ייטב לך and למען יאריכון ימיך, it refers to a world which is completely טוב and ארוך, which is in Olam HaBaah.
Onkelos explains אשר יעשה האדם means that if a person shall do them, וחי בהם, he will live with them everlasting life. This can be explained as Rashi; this refers to Olam HaBaah. This can’t refer to Olam HaZeh as he will end up dying.
The Ramban brings from the Gemara: Rav Yehuda said in the name of Shmuel: וחי בהם teaches that one should not die by fulfilling mitzvos. We derive from here that we are מחלל שבת and push away mitzvos to save someone who is in a possible danger of losing his life. Why does Onkelos translate different then the Gemara?
The Nesina LaGer answers that Onkelos translates differently than the Gemara in order to instill and implant in us our fundamental belief against the Tzaddukim. The saying goes “eat, drink, and be merry for tomorrow you will die.” Whatever pleasures and enjoyments they can get in this world they grab because they think that this is all there is. However, this is false. We believe that there is an afterlife in Olam HaBaah with our neshama. Everything we do in this world is accounted for and will contribute towards our reward and punishment. The Ramban adds each person creates his personal reward according to his level of fulfilling mitzvos.
May Hashem help us prepare our everlasting life in Olam HaBaah by fulfilling all His mitzvos.