What is the ruling of Islamic Law on following the actions of the imam in prayer and how this following is achieved?
Praise be to Allah, and peace and blessings be upon our master, the Messenger of Allah.
The follower (ma'mum) is required to follow his imam in the actions of the prayer. This "following" (mutaba'ah) means that the follower performs each action of the prayer after the imam has begun it but before he has finished it. For example, the follower bows (in ruku') after the imam has reached the position of bowing, then rises after the imam has risen. The Prophet, peace and blessings be upon him, said: "The imam is only appointed to be followed, so when he says the takbir, say the takbir; and when he bows, then bow; and when he prostrates, then prostrate" (agreed upon, i.e., reported by both al-Bukhari and Muslim).
It is stated in Mughni al-Muhtaj (1/505): "Among the conditions of valid congregational prayer (iqtida') is following the imam in the actions of the prayer... meaning that following the imam is obligatory in the physical actions of the prayer, not in its verbal utterances... Complete following (kamal al-mutaba'ah) is achieved when the follower's beginning of an action comes after the imam's beginning of that same action, while the follower's beginning of the action precedes the imam's completion of it" — end of quote, with slight paraphrasing.
And Allah, the Exalted, knows best.
Is it a condition for the mosque where I‘tikaf is performed to hold Jumu‘ah prayers?
No, it is not a condition for the mosque where I‘tikaf is performed to have Jumu‘ah prayers. However, if a person vows to perform continuous I‘tikaf, and Jumu‘ah occurs within that period, then they must observe I‘tikaf in a mosque where Jumu‘ah is held so that they do not break their continuity by leaving for Friday prayer.
Is it permissible for a praying person to make supplication in each Sajdah (a prostration) of obligatory prayer?
It is permissible for a praying person, whether praying individually, or in congregation, to make supplication during Sujood (prostration) in obligatory, or voluntary prayers. However, it is disliked for the Imam to do so since he is required to spare the prayer performers any sort of hardship, unless he is leading a certain group who don`t mind him extending the prayer.
"I told my family at night: 'I will fast tomorrow as qaḍā' (a make-up fast),' but I forgot to make the intention before sleeping. Is my fast valid?"
All praise is due to Allah, and peace and blessings be upon our master, the Messenger of Allah ﷺ.
The intention is obligatory in acts of worship. For obligatory fasting, the required intention is to resolve to fast during the night [before dawn]. Its proper locus is the heart, while verbalizing the intention out loud in acts of worship is a sunnah — so that the tongue may align with the heart. If the intent behind the statement in question was the intention to fast, then it is valid; but if the intent was merely to inform someone, or reflected hesitation or doubt, then it is not valid.
It is stated in *Bushrā al-Karīm* (Vol.1/P.216): "It is a sunnah to verbalize the intention — that is, whatever has already been intended in the heart, whether an obligatory or a voluntary act — such as specifying the number of rak‘ahs, just before the opening takbīr — so that the tongue may assist the heart, and because this is further removed from whispered doubts (waswasah), and in order to accommodate the view of those who held it obligatory in every act of worship that requires an intention (even though this is a minority position), by analogy with Ḥajj."
Accordingly: if the intention to fast arose in your heart before the second adhān [i.e., before Fajr], then your fast is valid.
And Allah, the Exalted, knows best.
