Meaning: The living and the dead. All humanity.
Acts 10:42
And he commanded us to preach unto the people, and to testify that it is he which was ordained of God to be the Judge of quick and dead.
2 Tim. 4:1
I charge thee therefore before God, and the Lord Jesus Christ, who shall judge the quick and the dead at his appearing and his kingdom;
1 Peter 4:5
Who shall give account to him that is ready to judge the quick and the dead.