Another explanation: If one has merited to learn Torah, he merits for himself as well as for all his future descendants.
"Take heed and hearken": Whoever is not in the class of learning is not in the class of doing.
"all of these things that I command you": A "slight" commandment should be as beloved by you as a "weighty" one.
"so that it be well with you (and with your children after you forever") If one merits learning, he merits it for himself and for his descendants until the end of all the generations. "if you do what is good and what is just": what is good in the eyes of Heaven and what is just in the eyes of man. These are the words of R. Akiva. R. Yishmael says: what is just in the eyes of Heaven and what is good in the eyes of man, as it is written (Proverbs 3:4) "and you will find grace and good regard in the eyes of G-d and man."