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.
There can be no difficulty to the Prophet in what Allah has indicated to him as a duty. It was the practice (approved) of Allah amongst those of old that have passed away. And the command of Allah is a decree determined.
(It is the practice of those) who preach the Messages of Allah, and fear Him, and fear none but Allah. And enough is Allah to call (men) to account.
Shafi, Muhammad (2008). Maariful Quran. (Vol .6 surah 33 verses 37-39). English-MaarifulQuran-MuftiShafiUsmaniRA-Vol-7.pdf (islamicweblibrary.com)