Idem per Idem

Twice in the book of Exodus where tradition preserves the revelation of the divine name to Moses, God employs a peculiar idiom which S. R. Driver has called the idem per idem. In Exod 3:14 God says:
I will be what I will be
and again in 33:19 he tells his servant:
But I will be gracious to whom I will be gracious
and I will show mercy on whom I will show mercy
The idem per idem is a tautology of sorts which Driver says is employed “where the means or the desire to be more explicit does not exist.” Driver calls the idiom Semitic, and indeed it is, as one can see by perusing the many examples from Hebrew and Arabic cited earlier by Paul de Lagarde in his Psalterium Iuxta Hebraeos Hieronymi. But it is also found, as we shall see in a moment, in other languages both ancient and modern.God's Use of the Idem per Idem to Terminate Debate Published online by Cambridge University Press: 10 June 2011 Jack R. Lundbom https://www.cambridge.org/core/journals/harvard-theological-review/article/abs/gods-use-of-the-idem-per-idem-to-terminate-debate/8A045FF63269EE49F52170DEFA059E04