﴿ وَٱلسَّلَٰمُ عَلَىَّ يَوْمَ وُلِدتُّ وَيَوْمَ أَمُوتُ وَيَوْمَ أُبْعَثُ حَيًّۭا ﴾

“"Hence, peace was upon me on the day when I was born, and [will be upon me] on the day of my death, and on the day when I shall be raised to life [again]!"”

وَبَرًّ‌ا بِوَالِدَتِي "and (He has made me) good to my mother." - 19:32. Here only the mother is mentioned and not both the parents. Hence it is implied that his birth was a miracle, being without a father. Such a discourse coming from an infant was a miracle by itself to prove his miraculous birth.