Who are the Riders in the Chariot?

from Patrick White’s The Rider’s In The Chariot, page 25:

Her father said:
‘Who are the riders in the Chariot, eh, Mary? Who is ever going to know?’
Who, indeed? Certainly she would not be expected to understand. Nor did she think she wanted to, just then. But they continued there, the sunset backed up against the sky, as they stood beneath the great swingeing trace-chains of light. Perhaps she should have been made afraid by some awfulness of the situation, but she was not. She had been translated: she was herself a fearful beam of the ruddy, champing light, reflected back at her own silly, uncertain father.’

I’m re-reading this amazing novel, in a lovely first edition I bought in Melbourne in 2004. When I first read it a few years ago, I loved the first section, describing the crumbling gothic world of Xanadu where Mary grows up and becomes old, but struggled with the Jewish section, which felt under-written, too discursive. However, I’m drawn back to it again, thinking I will read the middle part more sympathetically, and the sheer breath-taking magic of White’s prose, its poetry, its incisive psychology, its wit, the brilliance of the shape of the sentences and paragraphs. The image of the Riders in the Chariot haunts me every time I look up in the sky and see ‘the great swingeing trace-chains of light’.’