And in another narration:

"and he did not prostrate till Allah made him certain of this (i.e. as-Sahw)."

وَهِيَ فِي رِوَايَةٍ لَهُ : { وَلَمْ يَسْجُدْ حَتَّى يَقَّنَهُ اَللَّهُ تَعَالَى ذَلِكَ } .‏ [1]‏