Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: In the time of the Messenger of Allah (peace and blessings be upon him), a man killed another man. The Prophet (peace and blessings be upon him) set his blood money at twelve thousand dirhams. This was because in the noble verse it is stated, translation: "They swear by Allah that they did not say (it), but certainly the word of disbelief has come out of their mouths, and they disbelieved after their Islam, and they intended that which they could not attain. And they were not angry except due to the fact that Allah and His Messenger had enriched them from His bounty." (al-Tawbah: 74/9) That is, by taking the blood money.
Brief Explanation
(Commentary on Hadith 2399)
The background of this hadith and verse is as follows: There was a man who was previously a hypocrite. His client (mawla) was killed, so the Messenger of Allah sallallahu alayhi wa sallam arranged for him to receive blood money (diyah), and thus he became wealthy. Then he repented from hypocrisy and became a true believer. At that, the hypocrites became angry with him, and upon this, the verse: «﴿يَحْلِفُونَ بِاللّٰهِ .....﴾» was revealed.
In this hadith, "twelve thousand" refers to twelve thousand dirhams (silver coins), and their weight is forty-four kilograms.
Originally, the blood money (diyah) is one hundred camels, the details of which are coming ahead. If someone does not possess camels, the diyah can also be given in cash, whether the prevailing coin is dinar or dirham, or paper currency, equivalent to one hundred camels.
This hadith is authentic. Also, in Abu Dawud, it is narrated in musnad or mursal form from our master Jabir radi Allahu anhu that the Messenger of Allah sallallahu alayhi wa sallam fixed the diyah for those who own camels as one hundred camels, for those who own cows as one hundred cows, for those who own goats as two thousand goats, and for those who own cloth as two hundred garments...
Then, when our master Umar radi Allahu anhu became caliph, he fixed the diyah for those who own gold as one thousand dinars, and for those who own silver as one thousand dirhams...
And in the Muwatta, it is mentioned that our master Umar radi Allahu anhu fixed for those who own gold one thousand dinars, and for those who own silver twelve thousand dirhams. In the present era, according to the laws of Saudi Arabia, the diyah for one person is one hundred and twenty thousand Saudi riyals, which is approximately equivalent to one hundred camels, and this is correct. (And Allah knows best).