He slaughtered his sacrifice before the Prophet ﷺ did, so the Prophet ﷺ ordered him to repeat it.He said, "I have a young female goat that is dearer to me than two older ones."The Prophet ﷺ said, "Slaughter it."In the narration of Ubaydullah, he said, "I can only find a young goat," so the Prophet ﷺ ordered him to slaughter it.
أخبرنا عبيد الله بن سعيد قال حدثنا يحيى عن يحيى ح وأنبأنا عمرو بن علي قال حدثنا يحيى عن يحيى بن سعيد عن بشير بن يسار
أنه ذبح قبل النبي ﷺ فأمره النبي ﷺ أن يعيد قال عندي عناق جذعة هي أحب إلي من مسنتين قال اذبحها في حديث عبيد الله فقال إني لا أجد إلا جذعة فأمره أن يذبح
[Its isnad is sahih] Ahmad narrated it (3/466) from Yahya bin Saeed Qattan with this chain, and it is in Al-Kubra, no. 4484. The teacher of Qattan is Yahya bin Saeed Ansari.