'Mournfully' in the Bible

In that day one will take up a taunt against you,and lament mournfully, saying,“We are totally ruined!He measures out the allotted land of my people.How He removes it from me!He allots our fields to traitors.”

You have said: “It is useless to serve God. What have we gained by keeping His requirements and walking mournfully before the Lord of Hosts?