Only a Muslim ruler or his deputy is entitled to execute the Hudud, so as to keep order, prevent transgression, and oppression, and provide security. A sinner has to repent to Allah, seek His Forgiveness and increase his good deeds. If he returns to Allah in genuine repentance, Allah will forgive him and pardon him out of His Grace and Clemency. Allah (Exalted be He) says,
And those who invoke not any other ilâh (god) along with Allâh, nor kill such person as Allâh has forbidden, except for just cause, nor commit illegal sexual intercourse - and whoever does this shall receive the punishment.
The torment will be doubled to him on the Day of Resurrection, and he will abide therein in disgrace;
Except those who repent and believe (in Islâmic Monotheism), and do righteous deeds; for those, Allâh will change their sins into good deeds, and Allâh is Oft-Forgiving, Most Merciful.
Allah also says,
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).
The Prophet (peace be upon him) said,
Islam wipes out (Part No. 22; Page No. 6) all that have gone before it (previous misdeeds); and repentance wipes out all that have been done before it.
He (peace be upon him) also said,
Whoever repents of sins is like a sinless person.
May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.