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1004 B
until the full number of their fellow servants and their brothers was reached who were to be killed, just as they had been killed
This implies that God had decided that a certain number of people should be killed by their enemies. This can be translated in an active form. Alternate translation: "until people had killed the full number of their fellow servants ... sisters whom God had decided people would kill, just as people had killed their fellow servants ... sisters" (See: rc://en/ta/man/translate/figs-rquestion)
their fellow servants and their brothers
This is one group of people described in two ways: as servants and as brothers. Alternate translation: "their brothers who serve God with them" or "their fellow believers who serve God with them"
brothers
Christians are often spoken of as being one another's brothers. Females were among those spoken of here. Alternate translation: "fellow Christians" or "fellow believers" (See: rc://en/ta/man/translate/figs-metaphor)