Should he recite Aayat al-Kursi aloud or silently?

Dear Brothers & Sisters,
As-Salaamu-Alaikum wa Rahmatullahi wa Barakatuh. (May Allah's Peace, Mercy and Blessings be upon all of you)
One of our brothers/sisters has asked this question:
I say Ayat Kursi at night before I go to bed. I read if you recite it Shatayn will not bother you. Do you have to reite it out loud or can you say it to yourself and still be protected?
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Answer:

Praise be to Allaah.

It was reported in Saheeh al-Bukhaari that Abu Hurayrah (may Allaah be pleased with him) said: “The Messenger of Allaah (peace and blessings of Allaah be upon him) entrusted me with the task of looking after the Zakaat of Ramadaan. Someone came to me and started to scatter the food about, so I grabbed hold of him and said, ‘I will take you to the Messenger of Allaah (peace and blessings of Allaah be upon him)!’… He (that intruder) said: ‘When you go to your bed, recite Aayat al-Kursi, then there will stay with you a protector from Allaah, and no shaytaan (devil) will approach you until morning comes.’ The Prophet (peace and blessings of Allaah be upon him) said, ‘He spoke the truth even though he is a liar; that was a shaytaan.’”

(Hadith no. 4624). It is Sunnah to recite it, and it should be recited in a voice that you can hear. And Allaah knows best.
Whatever written of Truth and benefit is only due to Allah's Assistance and Guidance, and whatever of error is of me. Allah Alone Knows Best and He is the Only Source of Strength.
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