What makes it abstract is that the scenes were not painted from life. They were conjured images from the imagination of the artist.
Reading stories from the Old Testament fueled the inspiration and brought brush to canvas in some outstanding images. What is presented here is abstract symbolism - light on the abstract and light on the symbolism. They border on realism to a minute degree only that the objects are generally recognizable as representational.
Regardless of the words that follow images they should not keep you from finding your own meaning and appreciation of the work.