Rambam-What Part of a Man Lives Forever- Yisodei Hatorah perek 4 halacha 9

The Rambam tells us which part of a person it is that lives forever. He says,

אין צורת הנפש הזאת מחוברת מן היסודות כדי שתפרד להם. ואינה מכח הנשמה עד שתהא צריכה לנשמה כמו שהנשמה צריכה לגוף. אלא מאת ה' מן השמים היא. לפיכך כשיפרד הגולם שהוא מחובר מן היסודות ותאבד הנשמה מפני שאינה מצויה אלא עם הגוף וצריכה לגוף בכל מעשיה לא תכרת הצורה הזאת. לפי שאינה צריכה לנשמה במעשיה. אלא יודעת ומשגת הדעות הפרודות מן הגולמים ויודעת בורא הכל ועומדת לעולם ולעולמי עולמים. הוא שאמר שלמה בחכמתו וישוב העפר על הארץ כשהיה והרוח תשוב אל האלהים אשר נתנה: 


"This form of the soul is not made up of the elements and therefore it does not break down into them. Also, the form of the soul does not have a spiritual force in the sense that it does not have the same needs as a spiritual force, like the spiritual force requires a physical body. This (form of the soul) comes from G-D from heaven. Therefore, when the physical body , that is made from the elements, breaks down and the spiritual force is lost, since it is not found to exist without a physical body (since it needs a physical body) for all of its actions, this form of the soul is not cut off since it does not need the spiritual force for it to work. In fact, it knows and attains knowledge that is separate from the physical body and it knows the creator of everything and it exists forever. It is the subject that King Shlomo refers to with his wisdom when he says(Ecclesiastes 12:7), 'And the dust returns to the earth as it was, and the spirit returns to G-D who gave it.'"

The Rambam is pointing out the difference between the spiritual force of a man and the actual soul of a man. The force that a man has to be able to walk, run and basically do all of his actions comes from a spiritual force that is connected to his physical body. This spiritual force is lost when the body of a man dies. However, the soul of a man lives forever. This soul is made up of the knowledge that a man acquires while he is alive. This is what the philosophers refer to as the acquired intellect.

This is why it is so important to learn as much as possible while still alive. The part of a man that lives forever only consists of that which he or she acquires in this world. Therefore, one who learns more and gains more knowledge has more of a world to come based on the knowledge that he or she has acquired. One must always keep this in mind and be careful not to waste their time. Through knowledge man lives forever.