Translation:

7. Therefore when thou art free (from thine immediate task) still labor hard

Notes (Tafseer)

6192. When thou art free: or when thou art relieved. The words understood may be: from thy immediate task, that of preaching to men, denouncing sin, and encouraging righteousness; or, from the difficulties that confronted thee. When that happens, that does not finish the labours of the man of Allah. It is only one step to them. He has constantly and insistently to go on. When there is rest from the task of instructing the world, the contact with the spiritual kingdom continues, and indeed it becomes more intimate and concentrated.