After a long journey and a decade of eager anticipation in the Promised Land, Sarah makes a fateful decision. Realizing that time is advancing—Abraham is now eighty-five and she is seventy-five—she initiates a dramatic step to ensure the continuation of Abraham's family line, fundamentally altering their household structure [שד״ל, ביאור יש״ר, ברכת אשר].
Because Hagar is already Sarah's maidservant and property, the act of bringing her to Abraham is not a physical acquisition. Rather, it is a matter of gentle persuasion. Sarah approaches Hagar with kind, appeasing words, convincing her of the profound privilege involved in joining her life to a holy man like Abraham [רש״י, מזרחי, שפתי חכמים, גור אריה].
Sarah's timing is highly deliberate. She waits exactly ten years from the moment they settle in Canaan, holding onto the hope that the divine promise of a great nation will materialize there. Only when she feels her own chances of giving birth have faded does she offer her maidservant to her husband [רד״ק, שטיינזלץ]. From this specific waiting period, a broader legal principle is derived: if a couple is married for ten years without having children, the husband must take another wife to fulfill the commandment to procreate [רש״י, אבן עזרא, תורה תמימה].
Crucially, this ten-year count only includes the time spent living within the land of Canaan; the years spent outside of the Land of Israel are excluded. Commentators disagree on how to apply this detail. One perspective suggests this exclusion was unique to Abraham, as God's promise of children was strictly conditional upon his arrival in the Land of Israel [רש״י]. However, the primary approach among commentators is that this serves as a general rule for everyone. Time spent outside the land does not count toward the ten years. If a childless couple lives abroad and then moves to the Land of Israel, the clock resets, granting them a fresh ten-year period in the hope that the holiness of the land will merit them a child [רמב״ן, הטור הארוך]. Bridging these views, some explain that living outside the land simply lacks the necessary spiritual merit to overcome barrenness, meaning the true count can only begin once a couple enters the land [גור אריה, פרדס יוסף].
When Sarah presents Hagar to Abraham, she does not offer her merely as a concubine, but rather as a full, legal wife. This establishes a pure, proper, and legally sound relationship between them [רש״ר הירש, שטיינזלץ]. Yet, this new status is strictly limited to Hagar's relationship with Abraham. She is never freed from her servitude to Sarah and remains her exclusive property. By maintaining this dynamic, Sarah ensures that she will retain ultimate authority over the upbringing and education of any child born, thereby protecting her own standing as the primary mistress of the household [העמק דבר, מלבי״ם, רש״ר הירש].