Surah Al Kafirun (سورة الكافرو

Al-Kafirun (Arabic: الكافرون‎, "The Unbelievers") is the name of the 109th chapter (surah) of the Quran. This surah is positioned in Para 30 which is also known as Juz Amma (Juz' 30).

Hadith / Hadees:
As for the esteem in which Muhammad (pbuh) held this surah, it can be judged from the following few hadith:

Abdullah ibn Umar has related that on many an occasions he heard Muhammad (pbuh) recite Surahs Qul Ya- ayyuhal- kafiroon and Qul Huwu-Allahu ahad in the two rakats before the Fajr obligatory prayer (namaz / salah) and in the two rakats after the Maghrib obligatory prayer i.e. salat in Islam.
Khabbab ibn al-Aratt says: "The Holy Prophet (upon whom be peace) said to me: when you lie down in bed to sleep, recite Qul ya-ayyuhal kafirun, and this was the Holy Prophet's own practice also; when he lay down to sleep, he recited this Surah."
According to Ibn Abbas, Muhammad said to the people: "Should I tell you the word which will protect you from polytheism? It is that you should recite Qul ya-ayyuhal kafirun when you go to bed."
Anas says that Muhammad said to Mu'adh bin Jabal; "Recite Qul ya-ayyuhal-kafirun at the time you go to bed, for this is immunity from polytheism."
Both Fardah bin Naufal and Abdur Rahman bin Naufal have stated that their father, Naufal bin Muawiyah al-Ashjai, said to Muhammad: "Teach me something which I may recite at the time I go to bed." Muhammad replied: "Recite Qul ya-ayyuhal kafirun to the end and then sleep, for this is immunity from polytheism." A similar request was made by Jabalah bin Harithah, brother of Said bin Harithah, to Muhammad and to him also he gave the same reply.
Muhammad recited in the two rakahs before the morning prayer and the two rakahs after the sunset prayer (salaah / salaat) on ten or twenty different occasions: Say O' al-Kafirun and say He is God, the One (surah 112: al-Ikhlas).

If you want to know about the significance or the importance of Surat Kafirun, then only a single statement from the Holy Prophet Muhammad (peace be upon him) will be enough in the regard of Surah al-Kafirun; ‘reciting this Sorah carries the reward of reciting a quarter of the Holy Qur’an (Al-Quran / Al-Qur'an).’
The only thing that can be concluded with this statement is that, this Surah is highly regarded in Islam and it has its own significance for the entire Muslim nationhood.
However, let’s see what this Sorat Kafirun offers us;
• If you recite this Surah, Shaitan stays away from you. It also keeps you safe from Shirk (of any kind).
• Reciting this Surah along with Surah Tawhid during the Salaat makes Allah forgive one’s sins.
• For the forgiveness of your children and the parents’ sins, recite Surah al-Kafiroon and at-Tawhid while offering your prayer.

It is also among the five Surahs that have been recommended to be recited during a journey, the others being Surah an-Nasr, at-Tawhid, al-Falaq and an-Naas. Reciting Surah al-Kafirun and at-Tawhid in compulsory prayers is a means for forgiveness of sins for the reciter, his parents and his children. If a person dies after reciting this Surah, it is as if he has died a martyr. Recitation of this Surah before sleeping keeps one safe the whole night.

Surah Al-Kafirun adalah surah ke-109 dalam al-Qur'an. Surat ini terdiri atas 6 ayat dan termasuk surat Makkiyah. Nama Al Kaafiruun (orang-orang kafir) diambil dari kata yang muncul pada ayat pertama surat ini. Pokok isi surat ini adalah tidak diizinkannya kompromi dalam bentuk mencampuradukkan ajaran agama.

Müfessirler Kâfirûn Sûresi’nin faziletiyle ilgili olarak Hz. Peygamber’in, “Kul hüvellahu ehad Kur’an’ın üçte birine denktir, Kul yâ eyyühel-kâfirûn ise dörtte birine denktir” buyurduğunu; Sahâbe’den birine, “Uyumak üzere yatağına yattığında Kul yâ eyyuhel-kâfirûn sûresini oku; bunu okursan şirk inancına sapmaktan korunursun” dediğini naklederler. (İbn Kesîr, VIII, 526; Şevkânî, V, 597-598)