The line, “no refuge could save the hireling and slave” in the third verse seems to have been inspired by Job 7:2—”As a slave earnestly desires the shadow, and as an hireling looks for the reward of his work...”
Good catch. I’d missed that entirely.
I thought it "sounded Biblical" but had never run down the quotation. Neat.
Also John 10:12-13 indicates that hirelings were not well thought of.
Holman Hunt, "The Hireling Shepherd". Packed with symbolism as only Hunt could pack it in . . . .