Translation:

7. Verily it is thy Lord that knoweth best which (among men) hath strayed from His Path: and He knoweth best those who receive (True) Guidance.

Notes (Tafseer)

5597. Men set up false standards of judgment. The right standard is that of Allah. For His knowledge is complete and all-embracing; He reads hidden motives as well as things that appear before men's sight; and He knows the past history in which the roots of present actions are embedded, as well as the future consequences of present actions.