Muhammad taking his son's wife

And when you said to the one whom Allah had blessed and whom you had favoured, “Keep your wife and be mindful of Allah,” while concealing within yourself what Allah was to reveal, fearing people, though Allah is more deserving of your fear. When Zayd had ended his marriage, We married her to you so that believers would have no hesitation regarding marriage to the former wives of their adopted sons. Allah’s command is always fulfilled.

33:37And when thou saidst unto him on whom Allah hath conferred favour and thou hast conferred favour: Keep thy wife to thyself, and fear Allah. And thou didst hide in thy mind that which Allah was to bring to light, and thou didst fear mankind whereas Allah hath a better right that thou shouldst fear Him. So when Zeyd had performed that necessary formality (of divorce) from her, We gave her unto thee in marriage, so that (henceforth) there may be no sin for believers in respect of wives of their adopted sons, when the latter have performed the necessary formality (of release) from them. The commandment of Allah must be fulfilled.