Hosea 4:8

‘They feed on the sin of my people, and set their heart on their iniquity.'

The ‘they' here might suggest that the priests are in mind as a distinctive body, becoming wealthy as a result of leading the people astray (feeding on the sin of His people). And the second charge is that they themselves then also set their minds on iniquity, being therefore without excuse either way.

There is a warning in this to any who minister in God's name, lest they use their position to obtain wealth for themselves. It is a reminder that it will then not be long before set their minds on iniquity. Wealth is a dangerous thing to possess, especially for a man of God, and many a ministry has been rendered powerless by the effects of wealth.

Alternately the ‘they' might simply refer to Israelites as taking advantage of fellow-Israelites even though they were God's people. Certainly all the people did at that time take advantage of the general sins of the people in order to enrich themselves. And all, apart from a few godly souls, set their hearts on iniquity. So the words could equally be seen as applying to Israelites.