Variantly (Devarim 11:22) "For if you will keep, keep all of this mitzvah": Whence is it derived that if a man heard a word (i.e., a command) of the words of the Torah first and he fulfilled it, then just as the first was fulfilled by him, so, the others will be fulfilled by him? From "If you keep (the first), then you will keep all of this mitzvah." The same applies (conversely [i.e., that he will forget them]) to one who learned the first things and forgot them. — But perhaps (the intent is [not the above]), but because he learned the first ones and forgot them, then just as the first ones will not be fulfilled by him, then the later ones, too, will not be fulfilled by him; it is, therefore, written (Ibid. 8:19) "And if you forget, you shall forget."
You will not raise your eyes from it before it vanishes, as it is written (Proverbs 23:5) "If you close your eyes over it, it will be gone. For it will make wings for itself like an eagle, and it will fly heavenwards." And it is written in Megillath Chassidim: "If you forsake me for a day, I will forsake you for two days."