John Calvin Commentary Isaiah 47:15

"Thus shall the things be unto thee wherein thou hast labored: they that have trafficked with thee from thy youth shall wander every one to his quarter; there shall be none to save thee." — Isaiah 47:15 (ASV)

So shall they be to you. After threatening destruction to those astronomers, he again returns to the Babylonians and threatens that they must not look for assistance from that source from which they expected it, and that they should not rely on those vain counsels with which they had long and eagerly troubled themselves in vain.

He calls them dealers, or, as we commonly say, traffickers—a metaphor taken from merchants, who are skilled in countless arts of deception and in impostures of every kind. For the princes do not consult in a manner fitting their rank, but traffic in disgraceful transactions. Although we may extend this to all the allies who aided the Babylonians, the Prophet focuses mainly on the diviners. When he adds, from your youth, he aggravates Babylon’s guilt, for she had been infected with this foolish belief from ancient times and had held this error as if it had been born with her.

Every one to his own quarter. It is supposed that the Prophet here speaks of the flight of the astrologers, meaning that each one will provide for his own safety. I fully agree with this, but I also think there is an allusion to the “quarters” of the heavens, which astrologers divide and measure to derive their predictions from them. He therefore ridicules their vain boasting: “They will withdraw into their quarters, but they will go astray, and there will be no means of protection.” If anyone chooses to apply it to the revolt of those whose help Babylon thought she could easily obtain at any time, I have no objection.