55:21

فَبِأَيِّ آلَاءِ رَبِّكُمَا تُكَذِّبَانِ

Transliteration:

Fabi-ayyi ala-i rabbikuma tukaththibani

Word by Word:

So which (of the) favors (of) your Lord will you both deny?

Translations:

Which, then, of your Sustainer's powers can you disavow?

Then which of the favours of your Lord will ye deny?

Which is it, of the favours of your Lord, that ye deny?

Between them is a barrier which they cannot pass.

So which of the favors of your Lord would you deny?