Charles Ellicott Commentary 1 Chronicles 19:16

"And when the Syrians saw that they were put to the worse before Israel, they sent messengers, and drew forth the Syrians that were beyond the River, with Shophach the captain of the host of Hadarezer at their head." — 1 Chronicles 19:16 (ASV)

They sent messengers. —Samuel, “Hadarezer sent and drew forth” (literally, made to come out: i.e., to war, 1 Chronicles 20:1). The name “Hadarezer” (Hadadezer) is important, as it helps us identify this campaign with that of 1 Chronicles 18:3–8.

Beyond the river. —The Euphrates, called Purât, Purâtu, by the Babylonians and Assyrians, Furât by the Arabs, and Ufrâtus by the ancient Persians. The name is derived from the Accadian Pura-nunu (great river). The Assyrian Purât, Hebrew Pĕrâth, is simply the word Pura with a feminine ending, so that this well-known name means “The River par excellence.” (Isaiah 8:7.)

The use of this phrase, “beyond the river,” to denote the position of the Eastern Aramæans, shows that the narrative borrowed here by the chronicler was originally written in Palestine. The Syriac and Arabic add here, “and they came to Hîlâm.” (So Samuel; see next verse.)

Shophach. —Samuel, “Shobach.” The letters p and b are much alike in Hebrew. The Syriac has Sh’bûk. Shophach may be compared with the Arabic safaka, “ to shed blood” (saffâk, a shedder of blood).

Went before them. — Commanded them. It thus appears that the suzerainty of Hadadezer was recognised by some Aramæan States lying east of the Euphrates.