recitation of 1st kalima
its because when taking away janazah the first kalima is recited which is called tahleel as well
The followings are briefed quotes of the link listed below:Praise be to Allah Who has created Time and has made some times better than others, some months and days and nights better than others, when rewards are multiplied many times, as a mercy towards His slaves. This encourages them to do more righteous deeds and makes them more eager to worship Him.The happy person is the one who makes the most of these special months, days and hours and draws nearer to his Lord during these times through acts of worship; he will most likely be touched by the blessing of AllahThe Muslim must understand the value of his life, increase his worship of Allah and persist in doing good deeds until the moment of death. Allah says (interpretation of the meaning):Among the special seasons of worship are the first ten days of the month of Dhu'l-Hijjah, which Allah has preferred over all the other days of the year. Prophet Muhammad (PBUH) says: "There are no days in which righteous deeds are more beloved to Allah than these ten days." The people asked, "Not even jihaad for the sake of Allaah?" He said, "Not even jihaad for the sake of Allaah, except in the case of a man who went out to fight giving himself and his wealth up for the cause, and came back with nothing."These texts and others indicate that these ten days are better than all the other days of the year, with no exceptions, not even the last ten days of Ramadan. But the last ten nights of Ramadan are better, because they include Laylat al-Qadr("the Night of Power"), which is better than a thousand months. Thus the various reports may be reconciled.The virtue of these ten days is based on the followings:Allah swears an oath by them, and swearing an oath by something is indicative of its importance and great benefit. Allaah says (interpretation of the meaning): "By the dawn; by the ten nights" [al-Fajr 89:1-2]. This refers to the first ten days of Dhu'l-Hijjah.The Prophet (PBUH) testified that these are the best days of this world, as we have already quoted aboveThe Prophet (PBUH) encouraged people to do righteous deeds because of the virtue of this season for people throughout the world, and also because of the virtue of the place - for the Hujjaaj (pilgrims) to the Sacred House of Allah.The Prophet (PBUH) commanded us to recite a lot of Tasbeeh ("Subhan-Allaah"), Tahmeed("Al-hamdu Lillaah") and Takbeer ("Allaahu akbar") during this time. 'Abdullaah ibn 'Umar (may Allaah be pleased with him and his father) reported that the Prophet (peace and blessings of Allah be upon him) said: "There are no days greater in the sight of Allah and in which righteous deeds are more beloved to Him than these ten days, so during this time recite a great deal of Tahleel ("La ilaaha ill-Allah"), Takbeer and Tahmeed."These ten days include Yawm 'Arafaah (the Day of 'Arafaah), on which Allah perfected His Religion. Fasting on this day will expiate for the sins of two years. These days also include Yawm al-Nahar (the Day of Sacrifice), the greatest day of the entire year and the greatest day of Hajj, which combines acts of worship in a way unlike any other day.These ten days include the days of sacrifice and of Hajj.Refer to question and link below below for the deeds Muslims should do on these ten days.
Praise be to Allaah. Allaah created the angels from light. The Prophet (peace and blessings of Allaah be upon him) said: "The angels were created from light, the jinn were created from smokeless fire, and Adam was created from that which has been described to you." (narrated by Muslim, 2996) The angels are by nature obedient to Allaah: "[they, i.e., angels] disobey not, (from executing) the Commands they receive from Allaah, but do that which they are commanded [al-Tahreem 66:6 - interpretation of the meaning] They are created in such a way that they do not eat or drink. Their food is tasbeeh (glorification of Allaah) and tahleel (saying Laa ilaaha ill-Allaah), as Allaah tells us concerning them (interpretation of the meaning): "They (i.e. the angels) glorify His Praises night and day, (and) they never slacken (to do so) [al-Anbiyaa' 21:20] The angels bear witness to the Oneness of Allaah, as Allaah says (interpretation of the meaning): "Allaah bears witness that Laa ilaaha illa Huwa (none has the right to be worshipped but He), and the angels, and those having knowledge (also give this witness); (He always) maintains His creation in justice. Laa ilaaha illa Huwa (none has the right to be worshipped but He), the All-Mighty, the All-Wise" [Aal 'Imraan 3:18] Allaah has honoured some of the angels by choosing them as Messengers, just as He has chosen some of mankind as Messengers: "Allaah chooses Messengers from angels and from men" [al-Hajj 22:75 - interpretation of the meaning] When Allaah created Adam and He wanted to honour him, He commanded the angels to prostrate to him: "And (remember) when We said to the angels: 'Prostrate yourselves before Adam.' And they prostrated except Iblees (Satan), he refused and was proud and was one of the disbelievers (disobedient to Allaah)'" [al-Baqarah 2:34 - interpretation of the meaning] The angels are a mighty creation, and they perform many tasks, and they are divided into many groups, which no one knows except Allaah. Some of them carry the Throne: "Those (angels) who bear the Throne (of Allaah) and those around it glorify the praises of their Lord, and believe in Him, and ask forgiveness for those who believe (in the Oneness of Allaah)…"[Ghaafir 40:7 - interpretation of the meaning] Among them is the one who brings down the Revelation to the Messengers. He is Jibreel (peace be upon him), who brought the Qur'aan down to Muhammad (peace and blessings of Allaah be upon him): "Which the trustworthy Rooh [Jibreel (Gabriel)] has brought down Upon your heart (O Muhammad) that you may be (one) of the warners" [al-Shu'araa 26:193 - interpretation of the meaning] Among them is Mikaa'eel, who is appointed in charge of the rain and vegetation, and Israafeel who is appointed to blow the Trumpet when the Hour begins. And among them are the recording angels who are appointed to watch over the sons of Adam and their deeds: "But verily, over you (are appointed angels in charge of mankind) to watch you, Kiraaman (Honourable) Kaatibeen -writing down (your deeds), They know all that you do [al-Infitaar :10-12 - interpretation of the meaning] Among them are those who are entrusted with the task of writing down all deeds, whether good or evil: "(Remember) that the two receivers (recording angels) receive (each human being), one sitting on the right and one on the left (to note his or her actions) Not a word does he (or she) utter but there is a watcher by him ready (to record it) [Qaaf 50:17-18 - interpretation of the meaning] Among them are those who are entrusted with the task of seizing the souls of the believers: "Those whose lives the angels take while they are in a pious state (i.e. pure from all evil, and worshipping none but Allaah Alone) saying (to them): Salaamun 'Alaykum (peace be on you) enter you Paradise, because of that (the good) which you used to do (in the world)" [al-Nahl 16:32 - interpretation of the meaning] And among them are those who are entrusted with the task of seizing the souls of the disbelievers: "And if you could see when the angels take away the souls of those who disbelieve (at death); they smite their faces and their backs, (saying): 'Taste the punishment of the blazing Fire'" [al-Anfaal 8:50 - interpretation of the meaning] Among them are the gatekeepers of Paradise and the servants of the people of Paradise: "And angels shall enter unto them from every gate (saying): Salaamun 'Alaykum (peace be upon you) for you persevered in patience! Excellent indeed is the final home!" [al-Ra'd 13:23-24 - interpretation of the meaning] And among them are the gatekeepers of Hell: "O you who believe! Ward off yourselves and your families against a Fire (Hell) whose fuel is men and stones, over which are (appointed) angels stern (and) severe" [al-Tahreem 66:6 - interpretation of the meaning] Among them are some who strive in jihaad with the believers: "(Remember) when your Lord revealed to the angels, 'Verily, I am with you, so keep firm those who have believed. I will cast terror into the hearts of those who have disbelieved, so strike them over the necks, and smite over all their fingers and toes'" [al-Anfaal 8:12 - interpretation of the meaning] On Laylat al-Qadr in the month of Ramadaan, the angels come down to witness goodness with the Muslims, as Allaah says (interpretation of the meaning): "The Night of Al-Qadr (Decree) is better than a thousand months (i.e. worshipping Allaah in that night is better than worshipping Him a thousand months, i.e. 83 years and 4 months). Therein descend the angels and the Rooh [Jibreel (Gabriel)] by Allaah's Permission with all Decrees" [al-Qadr 97:3-4] The angels do not enter a house in which there is a statue, picture (image) or a dog. The Prophet (peace and blessings of Allaah be upon him) said: "The angels do not enter a house in which there is a dog or an image." (Narrated by Muslim, 2106). Belief in the angels is one of the pillars of faith, and whoever denies it is a kaafir: "and whosoever disbelieves in Allaah, His Angels, His Books, His Messengers, and the Last Day, then indeed he has strayed far away[al-Nisaa' 4:136 - interpretation of the meaning]