Albert Barnes Commentary Jeremiah 2:25

"Withhold thy foot from being unshod, and thy throat from thirst: but thou saidst, It is in vain; no, for I have loved strangers, and after them will I go." — Jeremiah 2:25 (ASV)

God the true husband exhorts Israel not to run barefoot, and with parched throat, like a shameless adulteress, after strangers.

There is no hope — that is, it is in vain.