Matthew Poole and continuators on Jeremiah 2:18

18 And now what hast thou to do in the way of Egypt , to drink the waters of Sihor ? or what hast thou to do in the way of Assyria, to drink the waters of the river ?

What business hast thou there, or what dost thou expect from thence, or what need hast thou to go, or send Messengers thither, if thou wouldst but keep close to me.

Viz. Nilus, it signifies black, from whence called Melas by the Greeks, either from the blackness of the Land, it passed through, or of the soil it casteth up, see on Isa. 23.3.

Here and by the same words before is meant, to seek help from either place noting their strength, Isa. 8.6. A metaphorical Allegory wherein God minds them of two of their broken Cisterns, and shews them their folly to go so far when they might have been better supplied nearer home, as if God were notable to help them, compare ver. 36.

i. e. Euphrates often called so by way of eminency, the chief River of Assyria, Isa. 7.20.