فَلَمَّا أَسْلَمَا وَتَلَّهُ لِلْجَبِينِ
[37:103]
So when they both submitted and he threw him down upon his forehead,
So when they had both submitted their wills (to Allah), and he had laid him prostrate on his forehead (for sacrifice),
Then, when they had both surrendered (to Allah), and he had flung him down upon his face,