Inexperienced rulers are likely to become tyrants and to bring about all kinds of misgovernment. This happened (v. 12), but the Lord would stand up to plead and to judge (13). "The Lord will enter into judgment with the ancients." I understand this to mean, probably, that he would inspire the elders of the people, and strengthen them to state their grievance and pronounce the consequences.
Lord God of Hosts. The same as "Lord of Sabaoth" (Rom 9:29; James 5:4), or, Zebaoth, The hosts of the Lord are his angels, the ministers of the Lord and his people, or, the innumerable heavenly bodies in the firmament, all of which are the subjects of his will.