Who is the one who enforces the hudud (fixed Qur'anic punishments) on the one who has earned them?

Question:
May Allah reward you, Honorable Shaykh. This questioner asks about the one who enforces the hudud on the one who has earned them: is it the Imam, or anyone? Knowing that 'Umar ibn al-Khattab (may Allah be pleased with him) — knowing that 'Umar ibn al-Khattab (may Allah be pleased with him) said — he beheaded the one who did not accept the ruling of the Messenger of Allah.

Answer:
The hudud are enforced by the Sultan, because this is among his authorities, or by the one the Sultan delegates. The saying of the Messenger (peace and blessings be upon him): "Go, O Anis, to this woman of mine. If she confesses, stone her." This is a delegation in enforcing the hudud. And he (peace and blessings be upon him) said: He was with him and repeated the confession. He said: "Take him and cut him off." This is a delegation. So the Imam delegates the enforcement of the hudud. As for the action of 'Umar (may Allah be pleased with him), it was because this person was one whose blood was forfeit, who...
...who rejected the ruling of the Shari'ah and wanted to seek judgment by other than what Allah revealed. This is apostasy from his religion, and he became one whose blood was forfeit. 'Umar killed him because his blood was forfeit. And 'Umar had authorities that no one else had, due to his status with the Messenger (peace and blessings be upon him), his closeness to the Messenger. He and Abu Bakr were the ministers of the Messenger (peace and blessings be upon him) and his advisors. So he had a qualification that no one else had, may Allah be pleased with him. Yes.