Translation:

2. We have not sent down the Qur'an to thee to be (an occasion) for thy distress

Notes (Tafseer)

2535. Allah's revelation may cause some human trouble for two reasons: (1) it checks man's selfishness and narrowness of view, and (2) it annoys the wicked and causes them to jeer and persecute. These are mere incidental things, due to man's own shortcomings. As far as the trouble is concerned, the revelation is meant to give a warning, so that persecutors may be reclaimed, (and of course for men of faith it is comfort and consolation, though that point does not arise in this context).