Today is the Islamic new year, we have now entered year 1432 after Hijra (migration).

This is what is said on wikipedia about Hijra:

It is common to the question of hijra refers to the Prophet Muhammad and his followers made from Mecca to Yathrib in 622 AD

Muhammad and his followers had been subjected to persecution in Mecca, where they refused to confess his message. After having had contact with representatives of Yathrib for some time were the exodus in the spring and summer. Muhammad himself left Makkah later and arrived in Yathrib in September of that year. After the hijra Yathrib came to be called Madinat an-Nabi, which roughly translates as "City of the Prophet", who briefly became Medina. There is a saying that there began the development of the first Islamic society. The year when this was performed hijra is based on the Islamic calendar. It was after Muhammad's death that this was established, probably during Umar ibn al-Khattab Caliphate which was the second in line. The Islamic calendar (sometimes called the hijra calendar year of the hijra-year) determines when the Islamic holidays and memorial days earlier and since it is based on the moon, not the sun, as occurs, for each year, approximately eleven days earlier, according to the Gregorian calendar.

Muhammad (SAW)

۞ أَفَتَطۡمَعُونَ أَن يُؤۡمِنُواْ لَكُمۡ وَقَدۡ كَانَ فَرِيقٌ۬ مِّنۡهُمۡ يَسۡمَعُونَ ڪَلَـٰمَ ٱللَّهِ ثُمَّ يُحَرِّفُونَهُ ۥ مِنۢ بَعۡدِ مَا عَقَلُوهُ وَهُمۡ يَعۡلَمُونَ

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Have ye any hope that they will be true to you when a party of them used to listen to the word of Allah, then used to change it, after they had understood it, knowingly?

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Har ni något hopp om att de kommer att vara sann mot dig när ett parti av dem brukade lyssna på Allahs ord, används sedan för att ändra det, efter att de hade förstått det, medvetet?