Abdullah bin Abbas reported,

Ibn Abbas reported that a woman among the Ansar would scarcely have a child who survived, so she would vow that if a child of hers lived, she would raise him as a Jew. When the Banu al-Nadir were expelled, there were among them some sons of the Ansar. The Ansar said, "Messenger of Allah, our sons!" So Allah revealed this verse, "There is no compulsion in religion" [Baqarah 2:256].

Azami 12028

Sahih

في قوله تعالى: {لا إكراه في الدين}

عن ابن عباس قال

كانت المرأة من الأنصار لا يكاد يعيش لها ولد، فتحلف: لئن عاش لها ولد لتهودنه، فلما أجليت بنو النضير إذا فيهم ناس من أبناء الأنصار، فقالت الأنصار: يا رسول الله، أبناؤنا، فأنزل الله هذه الآية: {لا إكراه في الدين}.

الأعظمي 12028صحيح
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Tafsir of the great Quran
Chapter
Virtues of Surah Baqarah
Section
His saying, "There is no compulsion in religion. The right course has become clear from the wrong. So whoever disbelieves in false deities and believes in Allah has grasped the most trustworthy handhold with no break in it. And Allah is the Hearing, the Aleem"
Numbering
Jami al-Kamil 12028 (2nd edition)
Azami 12028