Al-Ahzab - 33:37

And when you said to him to whom Allah had shown favor and to whom you had shown a favor: Keep your wife to yourself and be careful of (your duty to) Allah; and you concealed in your soul what Allah would bring to light, and you feared men, and Allah had a greater right that you should fear Him. But when Zaid had accomplished his want of her, We gave her to you as a wife, so that there should be no difficulty for the believers in respect of the wives of their adopted sons, when they have accomplished their want of them; and Allah's command shall be performed.

Behold! Thou didst say to one who had received the grace of Allah and thy favour: "Retain thou (in wedlock) thy wife, and fear Allah." But thou didst hide in thy heart that which Allah was about to make manifest: thou didst fear the people, but it is more fitting that thou shouldst fear Allah. Then when Zaid had dissolved (his marriage) with her, with the necessary (formality), We joined her in marriage to thee: in order that (in future) there may be no difficulty to the Believers in (the matter of) marriage with the wives of their adopted sons, when the latter have dissolved with the necessary (formality) (their marriage) with them. And Allah's command must be fulfilled.

And 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.