COMMENTARY on 4:33
Mustafa Khattab:

Translation:
And We have appointed heirs to what has been left by parents and next of kin. As for those you have made a pledge to, give them their share.12 Surely Allah is a Witness over all things.
Commentary:
12   This pledge was a common practice before Islam between friends and allies—taking oaths to inherit each other. This practice came to an end with the revelation of verse 8:75 of the Quran. Although friends and allies do not have a share in inheritance anymore, they still can get some of the estate through bequest.

 

A. Yusuf Ali:

Translation:
To (benefit) every one, We have appointed shares and heirs 543 to property left by parents and relatives. To those, also, to whom your right hand was pledged, 544 give their due portion. For truly Allah is witness to all things.
Commentary:

543  Mawali, plural of Mawla; from the root wala, to be near in place or relationship, to follow. Mawla may therefore mean: (1) nearly related, (2) heir, (3) sharer or partner; these three meanings are implied here; (4) neighbour, or friend, or protector, or client (44:41); (5) lord or master (16:76).

544  When the emigration took place from Makkah to Madman, bonds and links of brotherhood were established between the "Emigrants" and the "Helpers," and they shared in each other's inheritance. Later, when the Community was solidly established, and relations with those left behind in Makkah were resumed, the rights of blood-relations in Makkah, and the Helper-brethren in Madinah were both safeguarded. This is the particular meaning. The more genera! meaning is similar; respect your ties of blood, of neighbourhood, and of friendly compacts and understandings. Be just to all.

 

Muhammad Asad:

Translation:
And unto everyone have We appointed heirs to what he may leave behind: parents, and near kinsfolk, and those to whom you have pledged your troth 41 give them, therefore, their share. Behold, God is indeed a witness unto everything.
Commentary:
41  I.e., wives and husbands (Abu Muslim, as quoted by Razi).