Although Moses was one hundred and twenty years old when he died, his eye was not dim, nor his vigor abated.
Observation number one: The fact that Moses lived to 120 is pretty darn impressive, but the fact that his eye was not dim (no loss of eyesight or intellect) and his vigor unabated (still energetic) borders on the miraculous. But there’s something more here. Moses slides into a group of people that are not often noted: those who have served God and lived with and for Him for a long while and seen the benefits of a relationship with God. Am I talking health and wealth? Not so much, but obedience to God can have health benefits.
For example, Paul instructs believers not to be anxious about anything. Anxiety and stress have given birth to an entire family of health disorders in the modern world. If I am living in obedience, I will not be stressed out and will be less susceptible to those anxiety disorders and stress-related illnesses. Will I be immune and ever-healthy? Unlikely. But the likelihood of catching these particular illnesses decreases.
Another example is in diseases like Alzheimer’s. Some studies indicate that keeping the mind active and alert may help stave off the disease. A life lived with God and constantly looking deeper into Who He is is a life lived with an active mind. Does that mean Christians will never get Alzheimer’s? That would be a ridiculous claim to make. But an active mind is less susceptible, so the likelihood of getting the disease decreases. Not to zero, but decreases, nonetheless.
Will obedience and a life devoted to God stave off all illness and prevent every malady? Absolutely not. Just look at Job. Will obedience guarantee longevity? Uh, no. Jesus was the single most obedient person ever and He was crucified at around 33 years old. Obedience will not increase my quantity of life one iota, but it will improve my quality of life, viz. my life will be filled with love and joy and peace and kindness and goodness and gentleness and self-control … and patience.
How do I apply this? Obey God. It will not stave off every malady — it might even invite some — but it guarantees that the Great Physician will be at my bedside throughout. It will not guarantee me long life — I’m not entirely convinced that longevity is all that desirable when Heaven is the alternative and there have been rather a large number of faithful who have been killed at an early (-ish) age for their faith — but it guarantees that The Life is with me through whatever time I have here. This is not a call to health, but a call to obedience that it may go well with me and that I may live long. I also may not. Which it turns out to be is God’s call.