Following the death and burial of Sarah, the Torah tells us, “Avraham was old, well into his old age, and Hashem blessed Avraham with everything” (24:1).
 
Why is it necessary for the Torah to tell us that Avraham is old? We are very much aware of Avraham’s advanced age from the entire story of the birth of Yitzchak. The Torah points out Avraham’s old age many times. He was 99 when Hashem appeared to him commanding him to perform a brit millah, and he was 100 at the birth of Yitchak. The Torah has reminded us again and again of Avraham’s old age. Why it is necessary to repeat it again now?
 
In addition, why does Avraham choose to send his servant to perform the important mission to find Yitzchak a wife? Why not go himself, or send Yitchak to choose his own wife?
 
The Netziv answers that it is precisely his old age that is the reason why he does not go himself. Avraham is either afraid that he will die while he is the middle of the mission and never return home to Yitzchak with the woman of his choice, or he is afraid that this feeling of his days being numbered will cause him to make a hasty decision in choosing a wife for Yitzchak. He felt that this mission needed to be done with great care and patience, not haste. So in essence, the fact that Avraham is old explains why he sent his servant and did not go himself and therefore it is necessary to repeat this well-know fact here.
 
Why then did Avraham not send Yitzchak to choose his own wife? It is possible that Avraham understood that after the Akeidah, Yitzchak was simply too holy to leave Eretz Yisrael. This fact was only revealed later to Yitzchak himself when Hashem forbade his leaving Eretz Yisrael (26:1-4) even during a time of a famine. Avraham may have understood instinctively that having been a korban who actually went up on the altar, Yitzchak simply could not leave the Holy Land.
 
Rav S.R. Hirsch points suggests another reason why Avraham did not send his son. Despite the fact that Yitzchak himself was 40 years old, after the death of his mother, he was unable to move on and to look forward to marriage. He is overcome by his mourning and inconsolable and therefore emotionally paralyzed from taking this next step in his life. The relationship between Sarah and her only son was so strong that Yitzchak felt so lost and unmotivated after her death. Avraham, who himself is getting older, must teach his son that life must move on after death and we must never give up hope. When Rivkah does appear, the Torah tells us (24:57) that Yitzchak is finally comforted for the death of his mother. It is not only because there is another woman in the house, (or as chazal say the berachot of the candles, challah and anan reappeared), but that Yitzchak was able to internalize the lesson his father was teaching him. By bringing him a wife and teaching Yitzchak to continue to live and build the future even after death, Avraham not only strengthened Yitzchak, but ensured the continuity of Am Yisrael of all future generations.
 
Historically, the strength of the Jewish people has always been to continue to live and to be strong even in the face of death and tragedy. This is the middah that Avraham taught us that stays with us both as individuals and as a nation.