Sabeans - not those of Arabia-Felix, but those of Arabia-Deserta, descending from Sheba, grandson of Abraham and Keturah (Gen 25:3). The Bedouin Arabs of the present day resemble, in marauding habits, these Sabeans (compare Gen 16:12).
I alone am escaped - cunningly contrived by Satan. One in each case escapes (Job 1:16, Job 1:17, Job 1:19), and brings the same kind of message. This was to overwhelm Job, and leave him no time to recover from the rapid succession of calamities - “misfortunes seldom come single.”