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400 B
400 B
Twelve years they had served
The events in verses 4-7 happened before verse 3. Your language may have a way of showing this.
they had served Kedorlaomer
They probably had to pay him taxes and serve in his army. AT: "they had been under the control of Kedorlaomer" (See: rc://en/ta/man/translate/translate-names)
they rebelled
"they refused to serve him" or "they stopped serving him"