“And he should shecht the bull offering before Hashem and the sons of Aharon, the Kohanim, should bring the blood to the mizbeach and sprinkle the blood around the mizbeach that is in the entrance of the Ohel Moad (Vayikra 1:5).”
The Gemara in Brachos (31b) describes the beginning of Shmuel HaNavi’s life in the following way. Chana was childless and she came to the Mishkan in Shilo to daven for a child. She promised Hashem that if Hashem will grant her a son, she will dedicate him to Hashem, meaning that she will bring him to Shilo—the place of the Mishkan—so he can live his life totally for Hashem.
Hashem answered her prayers, and Chana gave birth. After two years, she came to Shilo to bring korbanos and she also brought her son, Shmuel, as she promised Hashem. When they arrived she looked for a Kohen to shecht her korban, but couldn’t find one and Shmuel—her two-year-old son—paskened that even a Yisroel was allowed to shecht a korban and a Kohen is not needed. He learnt this halacha from the pasuk, “And he should shecht the bull before Hashem and the sons of Aharon—the Kohanim—should bring the blood and sprinkle the blood on the mizbeach …,” which implies that Kohanim are only needed from the time that they catch the blood, but they are not needed to shecht.
It seems that the custom—in those days—was that only Kohanim shechted korbanos, so Eli—who was the gadol hador—said to Shmuel, “Why did he do such a thing?” Shmuel proved his position from the pasuk. Eli replied to the young child, Shmuel, “Even though you spoke well, you issued a halachic ruling in front of your teacher, and anyone who gives a halachic ruling in front of his rebbe is liable for death!” Chana came and shouted before him (Eli): “I am the woman who stood here with you and prayed before Hashem. It was this boy I prayed for; and Hashem has granted me what I asked of Him.” Shmuel was spared, and stayed in Shilo with Eli HaKohen.
Chana’s words, “I am the woman who stood here with you,” and she did not simply say, “I am the woman who stood here,” implies that Chana wanted to stress that when she prayed for a child, not only was she standing, but Eli was also standing. Zera Shimshon asks: Why was it so important that Eli also stood at that time? What difference would it make if he was standing or sitting at the time Chana prayed? It would seem that this was only something incidental and not worth mentioning.
He answers—in light of what HaRav Yosef Karo (the author of the Shulchan Aruch 1488-1575)—wrote in the Bais Yosef (siman 102) that although one is forbidden to sit himself down within four amos of someone who davens, if one was already sitting and a second person came close to him and began to daven, he is not obligated to stand up, but can remain sitting.
However—adds the Bais Yosef—this person who began to daven close to someone who is sitting did not act properly. The reason for this is that a third person who sees him sitting will not know that he sat down before the other one started to daven, and it will give the impression that he is a heretic—since he is not also davening!
Therefore—continues the Bais Yosef—even though he is not obligated to stand if he is a person who painstakingly performs mitzvos with all of its details, it is preferable that he stands for two reasons. Firstly, not to disgrace the one who is davening for acting improperly and, secondly, not to disgrace himself for looking like a heretic! The Bais Yosef concludes that this was the reason that Eli stood when Chana prayed.
According to this, Zera Shimshon explains that Chana held that Shmuel was not liable for the death penalty, because he didn’t really pasken the halacha that even a non-kohen can slaughter a korban. He only related a type of prophecy that he had, and the prohibition is only to say a halacha derived from a person’s own intelligence. (Remember, he was only two years old at the time!)
To convince Eli of this, she explained to him that if he held that Shmuel had paskened using his own intelligence and, therefore, would be deserving of the death penalty, then he would be disgracing Shmuel for transgressing the prohibition to pasken in front of his teacher, and he would also be disgracing himself for not thinking of the derasha of Shmuel. She, therefore, reminded him that two years previously, when she prayed to have a child, Eli, himself, didn’t remain seated in order not to disgrace Chana and himself. He should, therefore, use the same reasoning here, not to disgrace himself and Shmuel and spare the life of her child, Shmuel!
In other words, the fact that Chana mentioned that Eli stood when she prayed for Shmuel was not an unimportant detail, but it was part of her argument to save Shmuel!