Or HaChaim on Exodus 23:13/אור החיים על שמות כ״ג:י״ג

1 ובבל אשר אמרתי, "and in all things that I have said, etc." The reason the Torah writes ובכל ..תשמרו instead of simply וכל אשר…תשמרו, is connected to the statement of the sages (Makkot 23) that the number of positive commandments is 248, corresponding to man's limbs, whereas the 365 negative commandments correspond to the number of sinews in the human body (compare Zohar volume one page 78). A person should not say: "I am going to observe a sufficient number of commandments in order to safeguard the health of my body. By writing ובכל, the Torah hints strongly that our good health and well being will depend on our observing all of the commandments.

2ושם אלוהים אחרים לא תזבירו, "and you shall not mention the name of other deities, etc." The Torah means that just as the observance of all the commandments will help man to make all of his 248 limbs and 365 sinews function properly, so there is also an overall protection for man which results from his denial of any form of idolatry. Anyone denying idolatry is considered as if he had accepted the entire Torah and would actively assist all those who are engaged in observing Torah and its commandments. As a result, all the various parts of such a person's body will enjoy protection even if he had not performed certain commandments (because the opportunity did not arise), or he had not been able to demonstrate that he would not violate certain of the Torah's injunctions if given a chance to do so. Such "overall" protection of a person due to his denial of idolatry would not accrue to him if he had ignored or violated one or more of the commandments deliberately, however. The limb or sinew which is "connected" to fulfilment of that particular commandment may then experience pain or malfunction.