||[There] he announced that his wife Sarah was his sister, and Abimelekh, king of Gerar, sent messengers and took Sarah.
Vayomer Avraham el-Sarah ishto achoti hi vayishlach Avimelech melech Grar vayikach et-Sarah.
||God came to Abimelekh in a dream that night. 'You will die because of the woman you took,' He said, 'She is already married.'
Vayavo Elohim el-Avimelech bachalom halaylah vayomer lo hinecha met al-ha'ishah asher-lakachta vehi be'ulat ba'al.
||Abimelekh had not come near her. He said, 'O Lord, will You even kill an innocent nation?
Va'Avimelech lo karav eleyha vayomar Adonay hagoy gam-tsadik taharog.
Literally, 'father-king.' This was a title given to Philistine kings, much like Pharaoh was given to Egyptian monarchs (Psalms 34:1, Rashi ad loc.; cf. Sefer HaYashar 65,66). Persian kings were given the title Padi-shach, which also means 'father-king.' In Hebrew, av means master as well as father. So the designation Avi-melekh may mean 'master-king' or arch-king. See note on Genesis 41:43.
The guilty nation was Sodom.