Eliezer stands before Rebekah's family, carefully crafting a persuasive argument to secure their consent for a marriage. He paints a detailed picture of Isaac's unique background, his miraculous origins, and his unmatched financial standing, presenting him as a highly blessed and ideal groom.
He begins by emphasizing that Isaac was born to Sarah, the primary wife and a relative the family knows well. As her son, Isaac naturally carries forward Abraham's exceptional character traits [מלבי״ם, ביאור שטיינזלץ]. Eliezer specifically mentions that this birth occurred in Sarah's old age, a detail that carries profound weight. The primary approach among commentators is that being a child of their later years made Isaac incredibly cherished and beloved by his parents [ספורנו, רד״ק, צאינה וראינה]. Furthermore, it clearly indicated that Sarah would not have any more children, securely cementing Isaac's position as the sole heir to the family's legacy [חזקוני, צאינה וראינה].
This detail also serves a very practical purpose. The family might have wondered how the son of the elderly Sarah could be an appropriate age for their young relative. By noting the late birth, Eliezer clarifies that Isaac himself is not actually an old man [העמק דבר]. Beyond the practical age difference, the mention of her old age establishes Isaac's absolute purity. During that time, cynics spread rumors that Sarah had conceived from Abimelech. A natural pregnancy might have left room for doubt, but a highly visible miracle at the age of ninety proved beyond question that the child was truly Abraham's. God does not perform miracles to uphold a lie, and this divine intervention stands as a testament to Isaac's inherent goodness and righteousness [פרדס יוסף, צאינה וראינה].
Having established Isaac's personal virtues, Eliezer shifts to his financial security. He declares that Abraham gave Isaac absolutely everything he owned. Even though Abraham had other children from another woman, his deep love for Sarah and Isaac led him to bestow all his wealth and honor upon this specific son [רד״ק]. This guarantees that Isaac's brothers will not claim any share of the inheritance [רשב״ם, הדר זקנים]. This reality serves as a powerful incentive for the family, highlighting the immense fortune awaiting the woman who marries him. In fact, Abraham specifically sent his servant to find a wife from his own relatives because he could not bear the thought of a foreign woman inheriting such vast wealth and prestige [בכור שור].
To ensure his words were taken seriously, Eliezer went beyond mere verbal claims. It is not uncommon in matchmaking for families to show off borrowed money or property just to impress the other side [צאינה וראינה]. Anticipating their skepticism, Eliezer produced physical proof. He presented them with a formal deed of gift, a binding legal document confirming that Abraham had already transferred all his assets to Isaac completely and legally [רש״י, מזרחי, גור אריה, ברכת אשר].