They are in some anxiety because their power is slipping out of their hands. Reminding human beings of their limitations. These worldly figures are unable to deal adequately with their limitations and to face their own death. In Chapter seven, the drama then shifts to two other pictures. One is the scene of worship by the people of God, represented by the twelve tribes of Israel.
Twelve is the number of completely.
The people of God is complete. Cosmic calamities or the forces of evil will not overcome them. The second picture is the scene presented in today's reading from Revelation. We have a powerful image of the victory of love. Before us is a multitude of people which no one can number, who have come through tribulation, dressed in white robes, joining with the heavenly chorus in a liturgy of praise to the lamb that has been triumphant.