Praise be to Allaah.
The scholars are unanimously agreed that the hadd punishment
can only be carried out by the imam (Islamic ruler) or his deputy. This is
in the people’s interests and is for the protection of their soul, their
wealth and their honour. The imam is able to carry it out because of the
power and authority he has, which make the people obey him, and because no
one can accuse the imam of being biased or negligent in carrying out the
hadd punishments. Thus the imam is able to carry out the hudood punishments
in the proper manner so that the shar’i goals will certainly be achieved.
Al-Mawsoo’ah al-Fiqhiyyah,
17/145.
It says in Fataawa al-Lajnah al-Daa’imah, 7/21:
The hadd punishments can
only be carried out by a Muslim ruler or one who takes the place of the
ruler. It is not permissible for individual Muslims to carry out the hadd
punishments because of the chaos and fitnah (tribulation) to which that will
lead.”
It also says (21/5-6):
No one can carry out the hadd punishments except the Muslim
ruler or his deputy, in order to maintain order and prevent anyone from
transgressing against others, and to protect against injustice. And the
sinner has to pray for forgiveness and repent to Allaah and do a lot of good
deeds. If he is sincere in his repentance towards Allaah, Allaah will accept
his repentance and forgive Him by His grace and kindness. Allaah says
(interpretation of the meaning):
“And those who invoke
not any other ilaah (god) along with Allaah, nor kill such person as Allaah
has forbidden, except for just cause, nor commit illegal sexual intercourse
and whoever does this shall receive the punishment.
69. The torment will be doubled to him on the Day of
Resurrection, and he will abide therein in disgrace;
70. Except those who repent and believe (in Islamic
Monotheism), and do righteous deeds; for those, Allaah will change their
sins into good deeds, and Allaah is Oft‑Forgiving, Most Merciful”
[al-Furqaan 25:67-70]
“And verily, I am indeed forgiving to him who repents,
believes (in My Oneness, and associates none in worship with Me) and does
righteous good deeds, and then remains constant in doing them (till his
death)”
[Ta-Ha 20:82]
And the Prophet (peace and blessings of Allaah be upon
him) said: “Islam erases whatever came before it, and repentance erases
whatever came before it.”.