Praise be to Allah.
There is a special day in Islam which Allaah has singled out for blessings which are not to be found in any other days. This day is Friday, to which Allaah guided the Muslims . It is the weekly festival of the Muslims, and it has many special features, some of which we will describe here:
1 – It was the teaching of the Prophet (peace and blessings of Allaah be upon him) to venerate this day, honour it and single it out for special acts of worship that belong exclusively to this day. In Fajr (early morning prayer) on Friday he used to recite the Soorahs (chapters) ‘Alif-laam-meem tanzeel’ (al-Sajdah, no. 32) and ‘Hal ata ‘ala’l-insaan’ (al-Insaan, no. 76).
Shaykh al-Islam Ibn Taymiyah (may Allaah have mercy on him) said: the Prophet (peace and blessings of Allaah be upon him) used to recite these two soorahs in the Fajr prayer on Friday because they refer to what happened and will happen on that day, for they speak of the creation of Adam, the resurrection and the gathering of mankind, all of which happened or will happen on a Friday. So reciting them on this day is a reminder to his ummah (nation) of what has happened and what is yet to come. This is one of the special features of Friday.
2 – It is mustahabb (recommended) to send lots of blessings upon the Prophet (peace and blessings of Allaah be upon him) on the day of Friday and the night before, because he said: “Send lots of blessings upon me on Friday and the night before.” (Narrated by al-Bayhaqi, 3/249; classed as saheeh (sound) by al-Arna’oot).
3 – Jumu’ah (Friday) prayers are held on this day; this is one of the most strongly-affirmed duties of Islam, and one of the greatest gatherings of the Muslims. It is the greatest and most obligatory gathering in which they come together, apart from ‘Arafah [a place near Makkah where the pilgrims stand and pray during the Hajj or pilgrimage]. Whoever neglects Jumu’ah prayers out of carelessness, Allaah will place a seal over his heart. The people of Paradise will be brought closer (to Allaah) on the Day of Resurrection and they will see Allaah sooner, commensurate with how close they were to the imam on the day of Jumu’ah and how early they came to Jumu’ah prayers.
4 – The command to do ghusl (take a bath for the purpose of purification) on Friday; this command is most emphatic.
5 – Wearing perfume on Friday; this is better than wearing perfume on any other day of the week.
6 – Cleaning the teeth with the siwaak (tooth stick); this is better than using the siwaak on any other day.
7 – Going to the prayers early.
8 – Keeping oneself busy with prayer, dhikr (remembering Allaah) and reading Qur’aan until the imaam comes out to give the khutbah (sermon).
9 – Listening attentively to the khutbah, because listening to it is obligatory according to the more correct of the two scholarly opinions. If a person fails to do that he is engaging in idle talk, and whoever does that has not prayed Jumu’ah. In al-Musnad a marfoo’ report [i.e., a report which is attributed to the Prophet (peace and blessings be upon him)] states: “The one who says to his companion, ‘Be quiet and listen,’ has not prayed Jumu’ah.” (Narrated by Ahmad, 2034; classed as hasan by al-Arna’oot. See Haashiyat Zaad al-Ma’aad, 1/377. Also narrated by al-Bukhaari (934) and Muslim (851), with the wording: “If you say to your companion, ‘Be quiet and listen,’ on a Friday when the imaam is delivering the khutbah, then you have engaged in idle talk.”)
10 – Reading Soorat al-Kahf (no. 18) during the day of Friday. It was narrated that the Prophet (peace and blessings of Allaah be upon him) said: “Whoever reads Soorat al-Kahf on a Friday, light will shine for him from beneath his feet to the clouds of the sky, which will shine on him on the Day of Resurrection, and he will be forgiven from one Friday to the next.” (Narrated by al-Haakim, 2/368; classed as saheeh by al-Arna’oot).
11 – It is a festival which is repeated every week. Ibn Maajah narrated in his Sunan that Abu Lubaabah ibn ‘Abd al-Mundhir said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘Friday is the best and greatest of days before Allaah, and it is greater before Allaah than the day of al-Adha (the Feast of Sacrifice) and the day of al-Fitr (the Feast of Breaking the Fast). It has five characteristics: on this day Allaah created Adam; on this day Adam came down to earth; on this day Allaah caused Adam to die; on this day there is an hour during which no one asks Allaah for something but He will grant it to him, so long as he does not ask for something haraam (forbidden); and on this day the Hour [i.e., the Day of Judgement] will begin, so there is no angel who is close to Allaah, no heaven, no earth, no wind, no mountain and no tree that does not feel some apprehension on Friday.” (Narrated by Ibn Maajah, 1084. Al-Busayri said: its isnaad is hasan, and it was classed as saheeh in Saheeh Abi Dawood, 888).
12 – It is mustahabb (recommended) to wear the best clothes one has on Friday. Imaam Ahmad narrated in his Musnad that Abu Ayyoob said: “I heard the Messenger of Allaah (peace and blessings of Allaah be upon him) say, ‘Whoever takes a bath on Friday, puts on perfume if he has some, wears his best clothes then goes out , walking in a dignified manner until he reaches the mosque, then he prostrates in prayer if he wants and does not disturb anybody, then he remains quiet until the imaam comes out and he prays, that will be an expiation from one Friday to the next.’” (Narrated by Ahmad in al-Musnad, 23059; classed as hasan by al-Ana’oot).
In Sunan Abi Dawood it is narrated from ‘Abd-Allaah ibn Salaam that he heard the Messenger of Allaah (peace and blessings of Allaah be upon him) say on the minbar (pulpit) one Friday: “There is nothing wrong with any one of you if he buys two garments for Friday other than his work day clothes.” (Narrated by Abu Dawood, 1078; classed as saheeh by al-Albaani in Saheeh Abi Dawood, 953).
13 – It is mustahabb on Fridays to perfume the mosque with incense. Sa’eed ibn Mansoor narrated from Na’eem ibn ‘Abd-Allaah al-Mujmir that ‘Umar ibn al-Khattaab (may Allaah be pleased with him) commanded him to perfume the mosque of Madeenah with incense every Friday until noontime. This is why Na’eem was called al-Mujmir (from the word tajmeer meaning perfuming with incense).
14 – It is a day on which sins are expiated. In Saheeh al-Bukhaari it is narrated that Salmaan al-Faarisi said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘No man takes a bath on Friday and purifies himself as much as he can, and makes his hair tidy, and puts on perfume, then goes out, and does not come between two people, then prays as Allaah decrees for him and listens attentively when the imaam speaks, but he will be forgiven for his bad deeds between this Friday and the other.’” (al-Bukhaari, 843).
15 – On Friday there is the “hour of response” which is an hour in which no Muslim asks Allaah for something but He will grant it. In al-Saheehayn it is narrated that Abu Hurayrah (may Allaah be pleased with him) said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘On Friday there is an hour in which no Muslim asks for something whilst he is standing in prayer, but it will be given to him” – and he demonstrated the shortness of that time with his hands. (Narrated by al-Bukhaari, 883; Muslim, 1406).
16 – On Fridays there is the khutbah (sermon) which is intended to praise and glorify Allaah, and to bear witness to His Oneness and to the Messengership of His Messenger, and to remind His slaves of His blessings, to warn them of His punishment and wrath, to advise them of that which will bring them closer to Him and His Paradise, and to forbid them that which will bring them closer to His anger and Hell. This is the purpose behind the khutbah and of gathering to hear it.
17 – It is the day on which it is mustahabb to devote oneself to worship and it has an advantage over other days by being characterized with all kinds of worship, obligatory and mustahabb. Allaah has made for the followers of each religion a day on which they devote themselves to worship and refrain from worldly work. So Friday is a day of worship, and in relation to other days it is like Ramadaan in relation to other months; the “hour of response” on Friday is like Laylat al-Qadr (the Night of Decree) in Ramadaan. Hence whoever gets it right on Friday, his whole week will be good, and whoever gets it right in Ramadan, his whole year will be good, and whoever gets it right on Hajj, his whole life will be good. Friday is the measure of the week, Ramadaan is the measure of the year and Hajj is the measure of one's life. And Allaah is the Source of strength.
19 – It is the day with which Allaah has exclusively favoured this ummah, and from which He led the People of the Book astray before them, as it says in al-Saheeh, where it is narrated from Abu Hurayrah that the Prophet (peace and blessings of Allaah be upon him) said: “The sun has never risen or set on any day better than Friday. Allaah guided us to it and led the people away from it. The people are behind us in this respect. It (Friday) is for us, Saturday is for the Jews and Sunday is for the Christians.” (Narrated by Ahmad, 10305, classed as saheeh by Ibn Khuzaymah, 3/114).
20 – It is the day which Allaah chose from among all the days of the week, just as He chose Ramadaan from among the months of the year and Laylat al-Qadr from among all the nights, and Makkah from among all places on earth, and Muhammad from all of mankind.
With regard to the second question, the Muslims have several special occasions, such as:
1 – The blessed month of Ramadaan, which is a month that has special characteristics. You will find more information in Question no. 13480.
2 – Eid al-Fitr (the Feast of Breaking the Fast). This is the first day of the month of Shawwaal, on which the Muslims express their joy at the blessing which Allaah has bestowed upon them by enabling them to complete the month-long fast of Ramadaan.
3 – The Day of ‘Arafah, which is the ninth day of the month of Dhu’l-Hijjah, the day of the greater Pilgrimage (Hajj), the greatest pillar of the Hajj. It has many virtues, details of which are to be found in question https://islamqa.info/en/answers/7284/virtues-of-the-day-of-arafaah.
4 – Eid al-Adha (the Feast of Sacrifice). The Messenger of Allaah (peace and blessings of Allaah be upon him) said: “The best of days is the Day of Sacrifice.” This is the tenth day of Dhu’l-Hijjah. It was narrated that ‘Uqbah ibn ‘Aamir said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) said: ‘The Day of ‘Arafah, the Day of Sacrifice and the Days of al-Tashreeq [the three days following the Day of Sacrifice] are a festival for us Muslims, and they are days of eating and drinking.’” (Narrated by al-Tirmidhi, 704; classed as saheeh by al-Albaani in Saheeh al-Tirmidhi, 620).