The four categories of follower: madrik, lahiq, masbooq and masbooq-lahiq

Not every follower joins the prayer, or stays in it, in the same way. There are four different situations, each with its own name and its own rules.

A Mudrik is someone who joins the imam right from the start and stays with him the whole way to the end. Every normal rule for a follower applies to them.

A Lahiq is someone who started with the imam but couldn't keep up with some or all of the prayer; maybe their wudu broke and they had to leave. Their rule: finish whatever rak'ahs they missed on their own first. If the imam's congregation is still going, they then join back in; if it's finished, they just complete the rest by themselves. In the rak'ahs they missed, they don't recite the Qur'an out loud or to themselves as an obligation, and they don't need to do a Sajdah Sahw for mistakes in those rak'ahs, just like a normal follower doesn't.

A Masbooq is someone who didn't start with the imam; the imam had already prayed some or all of a rak'ah before they arrived. Their rule: join the imam straight away in whatever rak'ah he's on. Once the imam finishes and says Salam, the Masbooq stands up and completes the rak'ahs they missed by themselves, but this time, they do recite the Qur'an in them, since it's now their own turn to pray those rak'ahs from the start.

A Masbooq-Lahiq is someone who joined late (like a Masbooq) and then also fell behind partway through (like a Lahiq). They deal with the falling-behind part first, the way a Lahiq does, and then handle the part they missed before joining, the way a Masbooq does.

Followers (muqtadis) fall into four categories, depending on when they joined the imam and whether they kept up with him throughout.

A Madrik (also spelled Mudrik) is a person who joins the prayer with the imam from the beginning until the end. All the rulings relating to a follower, mentioned already or given elsewhere, apply to this person.

A Lahiq is a person who follows the imam from the beginning but misses some or all of the prayer, for instance because their wudu broke and they had to leave. The ruling for a Lahiq is to first complete the missed rak'ahs, and then, if the congregation is still ongoing, to rejoin the imam and follow him; if the congregation has ended, to complete the remaining prayer alone. A Lahiq is treated as a follower in the missed rak'ahs; just as an ordinary follower does not recite aloud or perform Sajdah Sahw for their own mistakes, a Lahiq does not recite in the missed rak'ahs, nor perform Sajdah Sahw for mistakes made in them.

A Masbooq is a person who does not join the congregation from the beginning, the imam having already performed some or all of the rak'ahs before they joined. The Masbooq first joins the imam in the rak'ah under way. After the imam finishes the prayer, the Masbooq stands and completes the missed rak'ahs, this time with recitation, performing Sajdah Sahw if a mistake occurs. For the missed rak'ahs, the Masbooq completes with recitation (Al-Fatiha and another Surah) those that count, in the order of their own rak'ahs, first (for the remaining rak'ahs after that, no additional Surah is recited) and they sit for Tashahhud according to how many rak'ahs they themselves have prayed, not how many the imam had prayed.

A Masbooq-Lahiq is a person who joins the prayer after missing some rak'ahs, and then also misses further rak'ahs after joining. The Masbooq-Lahiq first completes the rak'ahs missed after joining the imam, exactly as a Lahiq would, and then completes the rak'ahs missed before joining, exactly as a Masbooq would.

The muqtadī is classified into four categories according to the point at which he joined the imam and whether he kept pace with him throughout the prayer.

The mudrik is one who is present with the imam from the takbīrat al-taḥrīmah through to the conclusion of the prayer; every ruling applicable to a muqtadī, whether already discussed or discussed elsewhere, applies to him without qualification.

The lāḥiq is one who began the prayer with the imam but was prevented (say, by a ḥadath requiring him to leave for wuḍūʾ) from completing some or all of the rakʿāt alongside him. His rule is to make up (qaḍāʾ) the missed rakʿāt alone first; if the jamāʿah is still in progress on his return, he rejoins and follows the imam; if it has ended, he completes the remainder alone. In the rakʿāt he makes up, the lāḥiq retains the status of a follower; he does not recite, precisely as an ordinary muqtadī does not, and does not perform sajdat as-sahw for a mistake occurring within them, the imam's sahw (or its absence) governing him as it does any other muqtadī.

The masbūq is one who did not join from the outset, the imam having already completed one or more rakʿāt before he arrived. He joins the imam in whichever rakʿah is under way; on the imam's salām, he rises to complete the rakʿāt he missed, this time reciting in them himself, as they are now, in effect, his own rakʿāt from the beginning of his prayer, and performing sajdat as-sahw should an error arise. In completing these rakʿāt, he observes ḍamm al-sūrah and the qaʿdah according to the count of his own rakʿāt, not the imam's; the rakʿah in which he joined the imam counts as his first, irrespective of its position in the imam's own prayer.

The masbūq-lāḥiq is one who, having joined after missing rakʿāt, subsequently falls behind again after joining. He resolves the lāḥiq portion of his prayer first (the rakʿāt missed after joining the imam, made up exactly as a lāḥiq would) and only then addresses the masbūq portion, the rakʿāt missed before he joined, exactly as a masbūq would.