SHES RAB DON

don is a real workhorse of a word, you could click on the link and see at dharmadictionary all the terms. Here let's use either purpose, or meaning. Those two are good starting candidates when translating don. So we have the purpose of discriminating awareness, or the meaning of wisdom. The ninth chapter in Bodhisattva Way of Life is indeed the shes rab le'u, Wisdom chapter, le'u is chapter, so it's appropriate that the opening lines provide the starting point for this chapter.
So far in the second verse we have meaning of wisdom by the Sage (Buddha), thub pas shes rab don. Next we need a particle and an ending verb, and then we could translate the whole second line.