RobH_en_tn/rev/07/01.md

General Information:

John begins to describe a vision of 144,000 servants of God who become marked with seals. Their marking takes place after the Lamb opens the sixth seal and before he opens the seventh seal.

the four corners of the earth

The earth is spoken of as if it were flat and square like a sheet of paper. The phrase "the four corners" refers to the north, south, east, and west.