Abu Hurairah reported,

The Messenger of Allah ﷺ said, "Every human being is born by his mother upon the natural disposition, and afterwards his parents make him a Jew, a Christian, or a Magian. If they are both Muslims, then he is a Muslim. Every human being whom his mother bears is poked by Satan in his sides, except for Maryam and her son."

Muslim 6761

Sahih

حدثنا قتيبة بن سعيد حدثنا عبد العزيز يعني الدراوردي عن العلاء عن أبيه

عن أبي هريرة

أن رسول الله ﷺ قال كل إنسان تلده أمه على الفطرة وأبواه بعد يهودانه وينصرانه ويمجسانه فإن كانا مسلمين فمسلم كل إنسان تلده أمه يلكزه الشيطان في حضنيه إلا مريم وابنها

مسلم 6761صحيح
Contents
Reference
Commentary
Ayat
Collection
Sahih Muslim
Book
Decree
Chapter
Meaning of "every child is born upon fitrah" and the ruling on the death of children of disbelievers and children of Muslims
Numbering
Darussalam 6761
Muslim 6761