This refers to Salome (not that Salome), the upright, powerful wife of Zebedee, whose anger terrifies her son because it embodies the entire and obstinate race of Israel. Salome, elderly woman as she is, is the one with the most courage and integrity.
‘Every time she turned upon him in anger he was overcome with fright because he felt that this wild severe voice was not hers, it was the ancient desert-roughened voice of the obstinate race of Israel.’
Source: Nikos Kazantzakis, The Last Temptation, trans. P.A. Bien (London: Faber and Faber, 1983), p. 177