What is the wisdom behind mentioning antithetical pairs in the Qur’an, such as: (خَافِضَةٌ رَافِعَةٌ - "that which lowers [some] and raises [others]") and (خَاشِعًا مُتَصَدِّعًا - "humbled [and] splitting apart")?

The first verse: (It will bring low [some] and exalt [others]) describes the Day of Resurrection, and it is considered a rhetorical "antithesis" (Tibaq) that combines two opposites, for it lowers and exalts simultaneously. This description indicates its intensity, as it exalts some people and lowers others, raising the fortunate to higher ranks and lowering the unfortunate to lower ones, just as it shakes things and displaces them.

The second verse: (Had We sent down this Qur’an upon a mountain, you would have seen it humbled and splitting asunder from fear of Allah) aims to draw attention to the greatness of the Qur’an and its impact, and expresses astonishment at the hardness of heart of those who are not affected by it. The meaning of the verse is that if the mountain were in the place of these people who turn away from the Qur’an, it would have been admonished and split asunder from the fear of Allah, meaning it would have cracked and trembled out of fear of Allah.