Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings of Allah be upon him) said: "The blood of any man who testifies that there is no god but Allah and that I am the Messenger of Allah is not lawful, except in three cases (even if he is a Muslim): a life for a life, a married adulterer, and one who leaves his religion and separates from the community of Muslims."
Hadith Referenceسنن دارمي / من كتاب الاحدود / 2335
Hadith Gradingتحقیق (حسین سلیم أسد الدارانی):إسناده صحيح والحديث متفق عليه، [مكتبه الشامله نمبر: 2344]
From these two hadiths, it is understood that any Muslim who commits these major sins (kabirah) becomes lawful of blood (halal al-dam) and will be punished. If any Muslim intentionally kills another Muslim, then in retaliation his head will also be severed. Similarly, if someone who is married violates the honor and chastity of Muslim sisters and daughters (i.e., commits adultery), his blood is lawful and he will be stoned to death; and if the perpetrator is unmarried, he will be given one hundred (100) lashes. Likewise, if a Muslim becomes an apostate (murtad), then shedding his blood is permissible and correct, and such a person is a disbeliever (kafir) and expelled from the community of Muslims; he will be killed. It is thus clear that murder, adultery, and disbelief are such grave crimes that whoever commits them—even if he professes "La ilaha illallah Muhammadur Rasulullah"—will still be killed.
In Saudi Arabia, these matters are implemented, and those who commit these sins are punished according to the Shariah. By virtue of this, peace and security are established here, and life and property are relatively safe.
«أدام اللّٰه هذه البركات فى هذه البلاد الطاهرة.» Ameen.