Translation:

42. So leave them to plunge in vain talk and play about until they encounter that Day of theirs which they have been promised!

Notes (Tafseer)

5703. Their talk, their scepticism, is vain, because all spiritual evidence is against it; it is like the foolish play of people who do not think seriously. But the tremendous Day of Judgment and Reality will come, as described in the next two verses.