Midrasch zu Mischlej 27:11

Variantly: "For if you keep, keep, all of this mitzvah": Lest you say: I shall learn (only) this formidable section and leave this simple one, it is, therefore, written (Ibid. 32:47) "For it is not an empty thing from you." Something that you call "empty" is empty only from (i.e., because of) you. What you are calling "empty" is (Ibid.) "your lives" and length of days. Do not say "I have learned the halachoth; that is enough for me." It is, therefore, written "if you keep, keep, all of this mitzvah." Learn all of the mitzvah — midrash (Sifra and Sifrei), halachoth, and aggadoth. And thus is it written (Ibid. 8:3) "to make it known to you that not through bread alone shall a man live": "bread" is midrash. (Ibid.) "but by all that issues from the mouth of the L-rd shall a man live": These are halachoth and aggadoth. And thus is it written (Proverbs 27:11) "Grow wise, my son, and rejoice my heart, and I will answer my shamers in kind," and (Ibid. 23:15) "My son, when your heart becomes wise, then my heart, too, will rejoice." R. Shimon b. Yochai says: This tells me only of his father on earth. Whence do I derive (that this holds true also for) his Father in heaven? From "my heart, too, shall rejoice" — to include his Father in heaven.