They forgat the Lord, i.e. they revolted from him, as it is explained, 1 Samuel 12:10, and carried themselves as ungratefully and unworthily towards God, as if they had wholly forgotten his great and innumerable favours, and their infinite obligations to him. Forgetting of God is oft put for all manner of wickedness, whereof indeed that is the true cause. See Isaiah 17:10 Jeremiah 3:21 Ezekiel 22:12. This he saith, partly to answer all objection, That the reason why they desired a king was, because in the time of the judges they were at great uncertainties, and ofttimes exercised with sharp afflictions: to which he answereth by concession that they were so; but adds, by way of retortion, that they themselves were the cause of it, by their forgetting of God; so that it was not the fault of that kind of government, but their transgressing the rules of it; and partly to mind them that this their ungrateful carriage towards God was no new or strange thing, but an hereditary and inveterate disease, that so they might more easily believe their own guilt herein, and be more deeply humbled, both for their own and for their parents sins. They fought against them, to wit, with success, and subdued them.
Related Commentaries of 1 Samuel 12:9
1 Samuel 12:9
9 And when they forgat the LORD their God, he sold them into the hand of Sisera, captain of the host of Hazor, and into the hand of the Philistines, and into the hand of the king of Moab, and they fought against them.