Isa () is a classical Arabic name and a translation of Jesus. The name Isa is the name used for Jesus in the Quran. However, it is not the only translation; it is most commonly associated with Jesus as depicted in Islam, and thus, commonly used by Muslims. Arab Christians commonly refer to him by the name Yeshua (), an alternate form of the name Joshua.
Etymology
The English form of the name "Jesus" is derived from the Latin Iēsus and the Classical Latin IESVS (written on the Titulus/placard on the Cross - John 19:19), which in turn comes from the Greek (Iēsoûs). The Greek is a Hellenized form of the Hebrew name Yēšua (), which is in turn a shortened form of Hebrew Yehōšua () or "Joshua" in English. East Syriac literature renders the pronunciation of the same letters as ܝܫܘܥ ishoʕ (išoʕ) /iʃoʕ/. The Aramaic Bible (c. 200 AD) or the Peshitta preserve this same spelling. The Encyclopedia of the Qur'an by Brill Publishers quotes scholarship that notes that the Greek name Iesous, (Iēsoûs), also is known to have represented many different Biblical Hebrew names (which causes issues when seeking to find what Jesus' original Hebrew name would have been from the Greek) "Josephus used the Greek name lesous to denote three people mentioned in the Bible whose Hebrew names were not Yeshua', Y'hoshua' or Y'hoshua'. They were Saul's son Yishwi (Anglicized as 'Ishvi' in the RSV of I Samuel 14:49), the Levite Abishua' (mentioned in I Chronicles 6:4, etc.) and Yishwah the son of Asher (Anglicized as 'Ishva' in the RSV of Genesis 46:17). ... Josephus furnishes important evidence for the wide variety of Hebrew names represented in Greek by Iesous."
Also, the classical theologians Clement of Alexandria and Cyril of Jerusalem both stated that the Greek name Iesous was allegedly Jesus' original name.
There is a major discrepancy between the Hebrew/Aramaic and Muslim Arabic forms of this name, since the Hebrew form of this name has the voiced pharyngeal ʿAyin or ʿAyn consonant at the end of the name (as does Christian Arabic yasūʿ), while the Muslim Arabic form ʿīsā has the ʿAyn at the beginning of the name. It is also similar in the vowels to an Aramaic version of Jesus, viz. Eeshoʿ (Aramaic forms of the name, however, still have the voiced pharyngeal `Ayn consonant at the end of the name). [Other Aramaic pronunciations of the same name include yeshuuʕ (ʕ is IPA ayin). Vowels in Semitic languages are somewhat fluid between dialects while consonants are structurally more stable. The vowels in an Anglicized quote "Eesho`" by themselves are insignificant for this discussion since "i" and "e" and short "a" can interchange between dialects, and "u" and "o" can also interchange between dialects. The dominant consonantal discrepancy remains, between Aramaic yeshuuʕ [consonantal y-sh-w-ʕ] and Arabic ʕiisa [consonantal ʕ-y-s-alef].]
Scholars have been puzzled by the use of ʿĪsā in the Qur'an since Christians in Arabia used yasūʿ before and after Islam, itself derived from the Syriac form Yəšūʿ and ultimately Hebrew Yēšūaʿ by a phonetic change. The Encyclopedia of the Qur'an by Brill Publishers states this has also come about because many Western scholars have held a "conviction that Jesus' authentic Hebrew name is Yeshua'" and because of this they often "have been puzzled by the Qur'an's reference to him as 'Isa". Brill's Encyclopedia of the Qur'an further states "It is not certain that Jesus' original name was Yeshua'" However, the early Syriac/Aramaic form of the name Yeshua, the etymological link with 'salvation' (note the Hebrew consonantal root y-sh-`) in Matthew 1:21, all of the correspondences of in the Greek OT and Second Temple Jewish writings, and the common attestation of Yeshua among first century Jewish names have led to a consensus among scholars of the gospels that Yeshua was "Jesus"'s original name. "Esau" (and derivatives with `ayin as a first letter) is not a realistic possibility. With all this in mind, some scholars have proposed a number of explanations. James A. Bellamy of the University of Michigan suggested that the quranic name is a corruption of Masīḥ itself derived from yasūʿ, suggesting that this resulted from a copyist error and an attempt to conceal the Arabic verb sāʿa/yasūʿu which has obscene connotations, though no evidence has been found to support this claim.
Josef Horovitz on the other hand holds that the quranic form is meant to parallel Mūsā (Moses). Similar pairs are also frequently found in the Quran as well which supports this theory. For example, compare Ismā‘īl and Ibrāhīm (Ishmael and Abraham) or Jālūt and Tālūt (Goliath and Saul). It is thus possible that the Arabs referred to him as Yasaʿ, but the Quran reversed the letters so as to parallel Mūsā.