Translation:

2. But the Unbelievers (are steeped) in Self-glory and Separatism.

Notes (Tafseer)

4148. The great root of Evil and Unbelief is Self-glory or Arrogance, as is pointed out in several places with regard to Satan; cf. below, xxxviii. 74-76. This leads to Envy and opposition or a desire to start a peculiar doctrine or sect of one's own, instead of a desire to find common grounds of belief and life, which lead to the Religion of Unity of Allah. This teaching of Unity was what the Pagans objected to in the holy Prophet (verse 5 below)!