Why do we pause after the Almighty’s saying: "So they will not delay for an hour" and then continue with "nor will they advance"? And is the letter Jim pronounced with an empty mouth, and what are its characteristics? And why are the lips pressed together in Iqlab without a gap? And when is the Basmalah recited in the middle of a Surah? And what is the vowel mark and what is its duration?

The fundamental principle regarding pausing (وقف) is that it is permissible in anything that does not distort the meaning. There is no obligatory or absolutely forbidden pause that would entail sin, unless the reciter intentionally alters the meaning by pausing at a place where it should not be paused. As the author of Al-Jazariyyah said: "There is no obligatory pause in the Qur’an, nor is there any forbidden one except that which has a reason." In the verse: (When their term comes, they will not remain behind an hour, nor will they precede [it]), continuous recitation (وصل) is more preferable. Mus'hafs indicate the preference for continuous recitation by placing the word (صلي) above the word "ساعة".

As for the Basmalah, the general rule is that it is permissible to recite it when starting in the middle of a Surah, and it is permissible to omit it by consensus everywhere except in Surah At-Tawbah (Bara'ah). There is a difference of opinion regarding Bara'ah; some completely prohibit it, while others permit it. Some scholars believe that whoever prohibits the Basmalah at the beginning of Bara'ah also prohibits it in its middle sections. And whoever permits it absolutely in parts [of other Surahs] may or may not recite the Basmalah in Bara'ah, based on considering the reason for its revelation being related to the sword.

As for the vowel sound (الحركة), its duration is the amount of time it takes to pronounce the letter. This is learned through receiving it from qualified teachers (Shuyukh), and it varies according to the state of recitation (slow recitation - tartil, moderate recitation - tadwir, fast recitation - hadr).