﴿ وَيَقُولُونَ مَتَىٰ هَٰذَا ٱلْوَعْدُ إِن كُنتُمْ صَٰدِقِينَ ﴾

“and so they ask, “When is this promise [of resurrection and judgment] to be fulfilled? [Answer this, O you who believe in it,] if you are men of truth!””

Please check ayah 34:30 for complete tafsir.