Previous verses mentioned the treachery and ill-will of the hypocrites. The present verses comfort the Holy Prophet ﷺ asking him not to grieve over the mischief made by the disbelievers for they cannot harm him in any way.
The last verse (178) carries a refutation of the false notion about disbelievers: How can they, while obviously prospering in the present world, be regarded as victims of Allah's wrath and rejection?