It is narrated from Sayyiduna Aswad bin Sari’ that the Prophet (ﷺ) sent a detachment on the occasion of the Battle of Hunayn: then the narrator mentioned the entire hadith and said: By Him in Whose hand is the life of Muhammad, every soul that is born into this world is created upon the natural disposition (fitrah) until its tongue expresses what is in its heart.
Hadith Referenceمسند احمد / مسند المدنيين رضي الله عنهم اجمعين / 16299