Jamieson, Fausset and Brown on Hosea 4:12

12. Instances of their understanding ("heart") being "taken away."

stocks--wooden idols (Jr 2:27; Ha 2:19).

staff--alluding to divination by rods (see on Eze 21:21, 22). The diviner, says Rosenmuller, threw a rod from him, which was stripped of its bark on one side, not on the other: if the bare side turned uppermost, it was a good omen; if the side with the bark, it was a bad omen. The Arabs used two rods, the one marked God bids, the other, God forbids; whichever came out first, in drawing them out of a case, gave the omen for, or against, an undertaking.

declareth--that is, is consulted to inform them of future events.

spirit of whoredoms--a general disposition on the part of all towards idolatry (Ho 5:4).

err--go astray from the true God.

from under their God--They have gone away from God under whom they were, as a wife is under the dominion of her husband.