Jamieson, Fausset and Brown on Hosea 9:10

10. As the traveller in a wilderness is delighted at finding grapes to quench his thirst, or the early fig (esteemed a great delicacy in the East, Is 28:4; Jr 24:2; Mi 7:1); so it was My delight to choose your fathers as My peculiar people in Egypt (Ho 2:15).

at her first time--when the first-fruits of the tree become ripe.

went to Baal-peor--(Nu 25:3): the Moabite idol, in whose worship young women prostituted themselves; the very sin Israel latterly was guilty of.

separated themselves--consecrated themselves.

unto that shame--to that shameful or foul idol (Jr 11:13).

their abominations were according as they loved--rather, as Vulgate, "they became abominable like the object of their love" (De 7:26; Psa 115:8). English Version gives good sense, "their abominable idols they followed after, according as their lusts prompted them" (Am 4:5, Margin).