This is the fifth issue: if a traveller prays behind a resident, he must complete the prayer, due to the Prophet’s saying, may Allah’s peace and blessings be upon him: “The imam has only been appointed to be followed.” (1)

And his saying, may Allah’s peace and blessings be upon him: “Pray what you catch, and complete what you miss.” (2) This encompasses everything a person catches and everything he misses.

Also, Ibn Abbas was asked, “Why is it that a travelling man prays two units on his own, but four when he is with the imam?” He replied, “That is the sunnah.” (3) By “sunnah,” he meant the sacred law in its inclusive sense, which includes what is obligatory.

Moreover, the Companions would pray four units behind Uthman ibn Affan at Mina while they were travelling. (4) These are four proofs, all indicating that the follower must follow his imam in completing the prayer.

Issue: If a traveller catches one unit of the imam’s four-unit prayer, how many units should he perform?

The answer: he performs three. If he catches two units, he performs two; if he catches three, he performs one; and if he catches the tashahhud, he performs four—due to the general import of the Prophet’s saying, may Allah’s peace and blessings be upon him: “And complete what you miss.”

“Or behind one about whom he is uncertain; or he enters into a prayer which he is required to complete, then it becomes invalid and he repeats it, …”

His statement, “Or behind one about whom he is uncertain.”

This is the sixth issue: if he prays behind someone concerning whom he is uncertain—whether he is