Look back to connect the question
The “Then” (فَ - Fa) at the beginning of the Ayah implies that we should look at what preceded it to see what we should connect the question in this Ayah to.
فَبِأَيِّ آلَاءِ رَبِّكُمَا تُكَذِّبَانِ
“Then, which of the Aalaa’ (wondrous acts of power) of the Lord of both of you will you both deny/declare to be false/dismiss/undermine?”.
The “Then” (فَ - Fa) at the beginning of the Ayah implies that we should look at what preceded it to see what we should connect the question in this Ayah to.
The first time this Ayah was mentioned it came after the mention of seven things ...
Now Allah is making us focus upon our origin ...
... and the origin of the Jinn.
Asking us whether we are still going to deny His wonders?
“Which of the Aalaa’ (wondrous acts of power) ... will you both deny/declare to be false/dismiss/undermine?”