Bodhisattva wisdom vs. Arhat Wisdom This answer says that:


  in terms of wisdom, a Hinayana arhat is more powerful than a
  bodhisattva before the 8th bhumi, because he abandoned afflictive
  obscurations while the bodhisattva abandons them from the 8th ground.


Is there a sutra (if not, a commentary) where I can read more about this?
The following quotes come from Shantideva's Bodhisattvacaryavatara as well as Maitreya's text on Buddha nature, and commentaries from Geshe Jamphel Gyaltsen.

In his commentary to Shantideva, verse 1, Geshe Jamphel Gyaltsen says:


  Compared with an arhat (foe destryer) the omniscience of a buddha is
  higher. This is because only the mind of a buddha has the ability to
  perceive the two truths (conventional truth and ultimate truth)
  simultaneously. The mind of a Hinayana arhat does not have that
  capacity.


In Maitreya’s Sublime Continuum: The Essence of a One Gone Thus, with Commentary by Gyaltsap Darma Rinchen, it says:


  The definition of a Sangha Jewel is an arya being endowed with any of
  the 8 qualities of knowledge and freedom, such as the knowledge of the
  mode of phenomena.


Geshe Gyaltsen commentary reads:


  We do not need all eight to be a Sangha Jewel. The last set of three
  are qualities of true cessation and an arya bodhisattva on the first
  uninterrupted path of the path of seeing doesn’t yet have true
  cessations in his continuum and therefore not those last four
  qualities related to freedom. The arya bodhisattva mentioned in the
  Uttaratantra is of the eighth ground/bumi upwards and this arya has
  abandoned all afflicted obstructions so they have the freedom of those
  afflictive obstructions but not of the knowledge obstructions, since
  only a buddha is free from them, but they are still called a Sangha
  Jewel. Therefore it is mentioned: any of those eight qualities.


With respect to the verse 72, "Qualities of the non-returner", the commentary is:


  The bodhisattva who is a non-returner goes to complete enlightenment
  with no return—it is irreversible. This is the bodhisattva from the
  eighth bumi on, and includes the ninth and tenth bumis.


And:


  The Sangha free from afflictive obstructions are the bodhisattvas from
  the eighth bhumi onwards. Before the eighth ground bodhisattvas still
  have the afflictive obstructions. This presentation is from the
  Prasangika Madhyamika point of view, who say that only from the eighth
  ground onwards the afflictive obstructions have been abandoned.


And:


  Why do the Hinayana arhats not have the indivisible four qualities of
  the Buddha, the non-abiding or ultimate, final nirvana? It is because
  they do not have the causes or the bases to achieve the ultimate
  nirvana that are produced at the time of the three pure bumis. Without
  producing causes, no results arise and therefore these Hinayana arhats
  are said to be far from the final nirvana. And: The Hinayana arhats
  have some level of purity but no perfection of purity and even the
  bodhisattva from eighth ground up still has the obstructions of
  omniscience and therefore the purity is not complete. To attain that
  perfection of purity of a buddha we first need the devotion to the
  Mahayana because only by way of the Mahayana path we can abandon both
  obstructions. A Hinayana practitioner with only renunciation [and no
  bodhicitta] who follows the Hinayana path will only abandon among the
  two types of obstructions the afflictive obstructions and will not
  attain the purity free from both obstructions.


In addition, Madhyamika Prasangika posit that the two vehicles are not differentiated in terms of wisdom because they both realize the same object. At times, we say that the wisdom of a bodhisattva has a greater capacity because (1) it realized emptiness by way of relying on countless reasonings while that of so-called Hinayana do not, and (2) it is conjoined with bodhicitta, whih makes it more powerful. We say that the wisdom is like an axe, and bodhicitta like a strong arm. Without a strong arm, one cannot uproot a tree even if he possesses the axe.