Iabe is an English transliteration of the Greek name "ιαβε". The Jewish Encyclopedia of 1901-1906 states that "ιαβε" was used in the writings of the Church Fathers to represent the Hebrew Tetragrammaton, "יהוה". Under the Article Heading, "Church Fathers and Magic Papyri", it says:

• "It was in connection with magic that the Tetragrammaton was introduced into the magic papyri and, in all probability, into the writings of the Church Fathers, these two sources containing the following forms, written in Greek letters: (1) "Iaoouee," "Iaoue," "Iabe,";...
• It is evident that (1) represents “יהוה”,...
• The three forms quoted under (1) are merely three ways of writing the same word, [i.e. “יהוה”] though "Iabe" is designated as the Samaritan pronunciation. ¹

For a full discussion of various transliterations (Jehovah, Yahweh) of the Tetragrammaton in English, and the discussion on its original pronunciation, see Tetragrammaton. This article only focuses on one aspect.

The Catholic Encyclopedia and Iabe [i.e. Jabe]

In the Article “Jehovah (Yahweh)” in The Catholic Encyclopedia of 1910, it says under the sub-heading “To take up the ancient writers”:²

• The judicious reader will perceive that the Samaritan pronunciation Jabe probably approaches the real sound of the Divine name closest; the other early writers transmit only abbreviations or corruptions of the sacred name.
• Inserting the vowels of Jabe into the original Hebrew consonant text, we obtain the form Jahveh (Yahweh), which has been generally accepted by modern scholars as the true pronunciation of the Divine name.
• It is not merely closely connected with the pronunciation of the ancient synagogue by means of the Samaritan tradition, but it also allows the legitimate derivation of all the abbreviations of the sacred name in the Old Testament.

Other sources that support Iabe

The Anchor Bible Dictionary, Volume 6 [1972] states:

• Instances of the divine name written in Greek letters, such as Iao (equivalent to “Yaho”), Iabe (known to the Samaritans, Theodoret [4th century A.D.], and Epiphanius), Iaoue, Iaouai (Clement of Alexandria [3rd century]), and Iae also favor the form “Yahweh” (NWDB, 453).

New Bible Dictionary (1962)says:

• " The pronounciation Yahweh is indicated by transliterations of the name into Greek in early Christian literature, in the form iaoue (Clement of Alexandria) or iabe (Theodoret; by this time Gk. b had the pronunciation of v)" ³

Footnotes

1.The Jewish Encyclopedia of 1901-1906.

2. The Catholic Encyclopedia of 1910.

3. The New Bible Dictionary (1962)