Short answer
A Jewish person becomes Muslim by saying the shahada with belief, with no ceremony. Much stays familiar: one God, Abraham and Moses, prayer, fasting, circumcision and food laws. What changes is belief in Jesus as the Messiah and a prophet, and in Muhammad ﷺ as the final messenger, and following the Quran and Sunnah in place of halakha.
A Jew becomes Muslim by sincerely saying the shahada; Hanafi jurists add that he should disown any belief contrary to Islam, which the shahada already implies. The duties of Islam begin from that moment, and worship missed before Islam is not made up. A marriage to a Jewish wife remains valid.
The four schools agree on this.
Explanation
Jews have accepted Islam since the Prophet's ﷺ own time. One of the best known was Abdullah ibn Salam, a leading rabbi of Madinah, whose story al-Bukhari records. Many commentators link to him the Quran's mention of a witness from the Children of Israel who testified to the truth and believed. The Prophet ﷺ said a person of the Book who believes in his own prophet and then in Muhammad ﷺ is rewarded twice.
What stays familiar:
- Strict belief in one God, with no partner or image.
- Love for Abraham, Moses, David and the prophets of Israel. See Prophet Musa.
- Circumcision, regular prayer, fasting, charity and modest dress.
- Careful food laws: no pork, and meat slaughtered by invoking God's name. See is kosher and Christian meat halal.
What changes:
- Jesus: a Muslim believes he is the Messiah, born of the virgin Mary, a true prophet who was not crucified and will return.
- Muhammad ﷺ: the final messenger to all people, and the Quran the final revelation.
- Law: the Sabbath laws give way to the Friday prayer. Islam permits some foods the Torah forbade, such as camel and certain fats, and allows meat with dairy, while it forbids all alcohol, including wine.
Your family remains your family. Keep ties with Jewish parents and relatives with kindness. See what Islam says about Jews, how to convert and telling your family.
The evidence
Quran, Surah Al-Ahqaf 46:10
قُلْ أَرَءَيْتُمْ إِن كَانَ مِنْ عِندِ ٱللَّهِ وَكَفَرْتُم بِهِۦ وَشَهِدَ شَاهِدٌۭ مِّنۢ بَنِىٓ إِسْرَٰٓءِيلَ عَلَىٰ مِثْلِهِۦ فَـَٔامَنَ وَٱسْتَكْبَرْتُمْ ۖ إِنَّ ٱللَّهَ لَا يَهْدِى ٱلْقَوْمَ ٱلظَّٰلِمِينَ ﴿١٠﴾
Say, "Have you considered: if the Qur'an was from Allah, and you disbelieved in it while a witness from the Children of Israel has testified to something similar and believed while you were arrogant...?" Indeed, Allah does not guide the wrongdoing people.
Many commentators link this to Abdullah ibn Salam, a rabbi who accepted Islam.
Quran, Surah Aal-i-Imraan 3:84
قُلْ ءَامَنَّا بِٱللَّهِ وَمَآ أُنزِلَ عَلَيْنَا وَمَآ أُنزِلَ عَلَىٰٓ إِبْرَٰهِيمَ وَإِسْمَٰعِيلَ وَإِسْحَٰقَ وَيَعْقُوبَ وَٱلْأَسْبَاطِ وَمَآ أُوتِىَ مُوسَىٰ وَعِيسَىٰ وَٱلنَّبِيُّونَ مِن رَّبِّهِمْ لَا نُفَرِّقُ بَيْنَ أَحَدٍۢ مِّنْهُمْ وَنَحْنُ لَهُۥ مُسْلِمُونَ ﴿٨٤﴾
Say, "We have believed in Allah and in what was revealed to us and what was revealed to Abraham, Ishmael, Isaac, Jacob, and the Descendants, and in what was given to Moses and Jesus and to the prophets from their Lord. We make no distinction between any of them, and we are Muslims [submitting] to Him."
Muslims believe in all the prophets of Israel.
Quran, Surah Aal-i-Imraan 3:93
۞ كُلُّ ٱلطَّعَامِ كَانَ حِلًّۭا لِّبَنِىٓ إِسْرَٰٓءِيلَ إِلَّا مَا حَرَّمَ إِسْرَٰٓءِيلُ عَلَىٰ نَفْسِهِۦ مِن قَبْلِ أَن تُنَزَّلَ ٱلتَّوْرَىٰةُ ۗ قُلْ فَأْتُوا۟ بِٱلتَّوْرَىٰةِ فَٱتْلُوهَآ إِن كُنتُمْ صَٰدِقِينَ ﴿٩٣﴾
All food was lawful to the Children of Israel except what Israel had made unlawful to himself before the Torah was revealed. Say, [O Muhammad], "So bring the Torah and recite it, if you should be truthful."
Some Torah food laws were specific to the Children of Israel.
Sahih al-Bukhari 97
Sahih... رجل من أهل الكتاب آمن بنبيه وآمن بمحمد ...
"A man of the People of the Book who believed in his prophet and then believed in Muhammad will have a double reward."
A Jewish convert's earlier faith is honoured.
Sahih al-Bukhari 2004
Sahih... فأنا أحق بموسى منكم ...
"I have a closer claim to Moses than you."
Moses remains central to a Muslim's faith.
Where the ruling is recorded
- Radd al-Muhtar (Ibn Abidin), Kitab al-Jihad, Bab al-Murtadd, on how a person becomes Muslim. Discusses disowning a former religion for Jews and Christians.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.