And [remember, O Muḥammad], when you said to the one on whom Allāh bestowed favor and you bestowed favor,1 "Keep your wife and fear Allāh," while you concealed within yourself that which Allāh is to disclose.2 And you feared the people,3 while Allāh has more right that you fear Him.4 So when Zayd had no longer any need for her, We married her to you in order that there not be upon the believers any discomfort [i.e., guilt] concerning the wives of their claimed [i.e., adopted] sons when they no longer have need of them. And ever is the command [i.e., decree] of Allāh accomplished.
Translation: Saheeh International (English)
1 Referring to the Prophet's freed slave, Zayd bin Ḥārithah.
2 i.e., Allāh's command to the Prophet (ﷺ) to marry Zaynab after Zayd divorced her. This was to demonstrate that a man may marry a woman formerly married to his adopted son.
3 i.e., feared their saying that the Prophet (ﷺ) had married the (former) wife of his son (which is prohibited by Allāh in the case of a true, begotten son).
O Messenger! When you said to the one whom Allah had blessed with the bounty of Islam, and you had favoured with freeing him - the person intended here is Zayd bin Ḥārithah may Allah be pleased with him - when he came to you seeking counsel in divorcing his wife Zaynab bint Jaḥsh, you said to him, “Keep your wife; do not divorce her, and be mindful of Allah by fulfilling His commands and refraining from the things He has not allowed” whilst, O Messenger, you were hiding within your heart that which Allah was going to expose: that Zayd should divorce her and He would command you to marry her. You were fearing the people and did not express that which you knew, when Allah is more deserving of your fear than the people. So when Zayd disinclined from her, and was happy at heart with divorcing her, he divorced her and I married you to her, so that there would be no sin on the believers if they were to marry the wives of their adopted sons after they had divorced them. Allah’s command will always come to pass, nothing can stop or obstruct it.