Hafiz Muhammad Ameen
(1) "Equal retaliation has been prescribed." That is, taking retribution (qisas) is permissible. It is legislated, but it is not obligatory or necessary; rather, in general circumstances, forgiveness is better.
(2) "A free person for a free person (the killer himself)"—In the era of ignorance (Jahiliyyah), some powerful tribes considered their slave equal to the free person of others, and their woman equal to the men of others. In exchange for one of their free men, they would kill ten free men of others. The Shari‘ah declared: Only the killer will be killed, whether he is free or a slave, a woman or a man, one or more. Some individuals have interpreted it as: "A free person will be killed for a free person, a slave for a slave," but this interpretation is incorrect. The killer will be killed in place of the murdered person, not just any free person or slave.
(3) "Some pardon"—That is, if retribution (qisas) is pardoned, whether all the heirs pardon or even if one heir pardons. In such a case, there will be no retribution; instead, blood money (diyah) will be due.
(4) "In a good manner"—When the heir has pardoned retribution (qisas), he should also show kindness in taking the blood money (diyah), such as accepting it in installments and not insisting on a lump sum payment, unless the killer can easily pay it all at once. Similarly, the killer should appreciate this kindness and make the payment diligently, and should not cause hardship to the heirs of the murdered person.
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 4785