Charles Ellicott Commentary Hosea 6:10

"In the house of Israel I have seen a horrible thing: there whoredom is [found] in Ephraim, Israel is defiled." — Hosea 6:10 (ASV)

House of Israel. —This phrase means Ephraim and Judah, which are subsequently distinguished. The “horrible thing” refers to polluting idolatry. This distinctive word occurs again in Jeremiah. According to the punctuation of the Hebrew, the reciter hesitates before pronouncing the “horrible thing” which grated through his teeth.