The figure of Eliezer intervenes. All that can be reasonably said is that the hand seems to belong with the shoulder. It seems so because the painter makes sure that there is enough to make the match between them probable. You have to look from one to the other, make an estimate and arrive at an inference. The inference carries no guarantee, because the connection between hand and shoulder is not discoverable, Should you scrape the figure of Eliezer off the canvas, you would find the painted ground or the canvas, but not the missing arm.
Painting has a potential for concealing as much as for making figures visible.
I might add that the figure of Eliezer consists almost entirely of drapery. He is covered almost from head to toe. There is also a left hand holding bracelets, in shadow against a dark ground. This comes as the termination of a sleeve. His face is largely in shadow and covered by his dark beard.