Philosophy had to turn Boethius's mind away from earthly things because one of the major arguments presented in The Consolation of Philosophy is that a focus on earthly things is the source of unhappiness. This is a Stoic position. Bad things will happen in the earthly realm, as Boethius well knew: he was imprisoned and sentenced to death on very flimsy charges. Formerly a rich and influential man, he was reduced to the status of a condemned prisoner. Classical Stoics generally held that such events occurred randomly, part of the machinations of the goddess Fortuna, whose spinning wheel was a metaphor for the incomprehensible nature of life's setbacks.
In the Consolation of Philosophy, Philosophy also employs the metaphor of Fortuna's wheel, but Boethius comes to understand that since God is all-knowing, things aren't truly random. Rather, they are simply not within the realm of human comprehension, at least not in their totality. A classical Stoic would likely argue that events occur randomly, that Boethius is trying to understand things that have no pattern, no rhyme nor reason, and that this must be borne with good cheer in order for life to be worth living. This, to some extent, is what Philosophy is arguing and is one reason why The Consolation of Philosophy is often viewed as an attempt to reconcile aspects of classical philosophy with Christian views of the omniscience of God. It is the cultivation of an internal life that matters, not the fleeting material world.