What is the wisdom behind the repetition of the phrase "Hayhāta Hayhāt" (Far be it, far be it) in the Qur'an without a separator, and are there other phrases repeated in the same manner?

The repetition in the word "hayhat" is for emphasis, and its meaning is "far is that which you are promised." Repeated phrases have appeared in the Holy Quran for emphasis, such as "Woe, that Day, to the deniers," and "No! They will soon come to know. Then, no! They will soon come to know," and "For indeed, with hardship [will be] ease. Indeed, with hardship [will be] ease." The repetition of the verse "Then which of the favors of your Lord will you deny?" in Surat Ar-Rahman is to affirm the blessing and emphasize its remembrance, which is a common style in Arabic speech for conveying and saturating meaning.