And he said, Open the window eastward. And he opened it. Then Elisha said, Shoot. And he shot. And he said, The arrow of the LORD'S deliverance, and the arrow of deliverance from Syria: for thou shalt smite the Syrians in Aphek, till thou have consumed them. Open the window eastward - This was towards the country beyond Jordan, which Hazael had taken from the Israelites.
The arrow of - deliverance from Syria - That is, As surely as that arrow is shot towards the lands conquered from Israel by the Syrians, so surely shall those lands be reconquered and restored to Israel.
It was an ancient custom to shoot an arrow or cast a spear into the country which an army intended to invade. Justin says that, as soon as Alexander the Great had arrived on the coasts of Iona, he threw a dart into the country of the Persians. "Cum delati in continentem essent, primus Alexander jaculum velut in hostilem terram jacit." - Just. lib. ii.
The dart, spear, or arrow thrown, was an emblem of the commencement of hostilities. Virgil (Aen. lib. ix., ver. 51) represents Turnus as giving the signal of attack by throwing a spear: -
Ecquis erit mecum, O Juvenes, qui primus in hostem?
En, ait: et jaculum intorquens emittit in auras,
Principium pugnae; et campo sese arduus infert.
"Who, first," he cried, "with me the foe will dare?"
Then hurled a dart, the signal of the war.
Pitt.
Servius, in his note upon this place, shows that it was a custom to proclaim war in this stay: the pater patratus, or chief of the Feciales, a sort of heralds, went to the confines of the enemy's country, and, after some solemnities, said with a loud voice, I wage war with you, for such and such reasons; and then threw in a spear. It was then the business of the parties thus defied or warned to take the subject into consideration; and if they did not, within thirty days, come to some accommodation, the war was begun.
Thou shalt smite the Syrians in Aphek - This was a city of Syria, and probably the place of the first battle; and there, it appears, they had a total overthrow. They were, in the language of the text, consumed or exterminated.