Call them by [the names of] their fathers; it is more just (33:5)

Almuntakhab Fi Tafsir Alquran Alkarim

Relate them to their fathers. This is a recourse sanctioned by Allah and if you do not know their fathers nor can you trace them, then they are members of your brotherhood and your co-religionists. You are absolved of what you erroneously did in the past but not of what you resolved where the guilt resided in the intention, but Allah has always been Ghafurun (Forgiving) and Rahimun (Merciful)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(33:5) Call your adopted sons after their true fathers; that is more equitable in the sight of Allah. *8 But if you do not know their true fathers, then regard them as your brethren in faith and as allies. *9 You will not be taken to task for your mistaken utterances, but you will be taken to task for what you say deliberately. *10 Allah is Most Forgiving, Most Compassionate. *11

Call them by [the names of] their fathers; it is more just meaning

*8) The first reform introduced in connection with the implementation of this Command was that Zaid, the adopted son of the Holy Prophet, began to be .called Zaid bin Harithah, after his real father, instead of Zaid bin Muhammad. Bukhari, Muslim, Tirmidhi and Nasa'i have related this tradition from Hadrat 'Abdullah bin `Umar that in the beginning the people called Zaid bin Harithah Zaid bin Muhammad. After the revelation of this verse they began calling him Zaid bin Harithah. Moreover, after this Revelation it was forbidden that a person should assign his parentage to any other man than his own real father. Bukhari, Muslim and Abu Da'ud have related on the authority of Hadrat Sa'd bin Abi Waqqas that the Holy Prophet said: "Paradise is forbidden for the one who called himself son of another person than his own father. " Other traditions bearing on the subject have been related in Ahadith, which have regarded this as a heinous sin.
*9) That is, even in such a case it will not be right to ascribe the parentage of a person to someone else.
*10) It means: "There is no harm if a person is called a son out of love. Likewise, there is no sin if someone calls another one a mother, or a daughter, or sister or brother, etc. out of affection and regard, but if such a thing is said with the intention that the one being called so will be accorded the same status and position and rights and privileges as actually belong to these relations, it would certainly be objectionable and one will be held answerable for it. "
*11) That is, 'Allah has forgiven the errors already committed in this regard; no one will be called to account for them." Another meaning is: "Allah does not call a people to account for actions done unintentionally. He will not punish a person for doing something which he did not do intentionally although it resembled a forbidden act apparently."
 

Call them by [the names of] their fathers; it is more just meaning in Urdu

منہ بولے بیٹوں کو ان کے باپوں کی نسبت سے پکارو، یہ اللہ کے نزدیک زیادہ منصفانہ بات ہے اور اگر تمہیں معلوم نہ ہو کہ ان کے باپ کون ہیں تو وہ تمہارے دینی بھائی اور رفیق ہیں نا دانستہ جو بات تم کہو اس کے لیے تم پر کوئی گرفت نہیں ہے، لیکن اُس بات پر ضرور گرفت ہے جس کا تم دل سے ارادہ کرو اللہ درگزر کرنے والا اور رحیم ہے