Arethas or Aretas (Arabic: الحارث بن كعب, romanized: Abdullah al-Ḥārith bin-Kaʿb) was the leader of the Miaphysite Christian community of Najran in the early 6th century; he was executed during the persecution of Christians by king Yemen Yusuf As'ar Dhu Nuwas of Himyar in 523.

[3][4] This tragic story spread quickly to the surrounding areas until it reached the ears of Emperor Justin I of the Byzantine Empire.

He then sent Christian troops from Abysinia to stop King Dhu Nuwas.

He is known from the Acta S. Arethae (also called Martyrium sancti Arethae or Martyrium Arethae)[5] which exists in two recensions: the earlier and more authentic, which was found by Michel Le Quien (Oriens Christianus, ii.

428) and was subsequently dated as no later than the 7th century; the later, revised by Simeon Metaphrastes, dates from the 10th century.