Muḥammad is not the father of [any] one of your men, but [he is] the Messenger of Allāh and seal [i.e., last] of the prophets. And ever is Allāh, of all things, Knowing.
Muhammad is not the father of any of your men, so he is not the father of Zayd, therefore his marrying his wife is not impermissible for him when Zayd divorces her. However, he is the Messenger of Allah sent to the people and the seal of the prophets: there is no prophet to come after him. Allah is the knower of everything, nothing is hidden from Him from the affairs of His servants.