1 Kings 2:21

And she said, Let Abishag the Shunammite be given to Adonijah thy brother to wife.

Cross-reference

2 Samuel 16:21 Historical context

2 Samuel 16:21 advises taking a king's concubine to assert power — the same political logic behind Adonijah's request for Abishag.

2 Samuel 16:22 Historical context

2 Samuel 16:22 shows Absalom actually taking the concubines, fulfilling the advice — a direct parallel to the power move Adonijah attempts.

2 Samuel 3:7 Historical context

2 Samuel 3:7 records another case of taking a royal concubine (Rizpah) to claim power — the same political strategy as Adonijah's request.