In the haftara of Parshat VaYeira, also read as the haftara on the second day of Rosh HaShana, we read of the miraculous birth of a son to the Shunamite woman through the blessing of Elisha, his early death and subsequent miraculous resurrection. Wanting to repay the Shunamite woman for her kindness in hosting him and even building a special room for him - after she refuses his former offers of assistance - Elisha blesses her with a son. The Midrash (Yalkut Shimoni 228) comments that she, like Sara before the birth of Isaac, was barren and had passed the natural age of fertility. Miraculously, she does have son. How strange it is then, that this child, born as a result of so many miracles, should die when just a young boy! Indeed, when Elisha initially blesses her, he states "at this time... you will embrace a son" to which the woman responds "do not disappoint your maidservant" (2 M'lachim 4:16). Rashi and Malbim comment that the Shunamite woman inferred from Elisha's initial words that her son might not survive - as if Elisha stated "you will embrace him but he might not live a long life." She therefore beseeched him that her son should live. How can we understand this child's premature death?
Rav Meir Leibush Malbim, in his commentary to the Akeida in our parsha (VaYeira 22:9), states that since Yitzchak was born miraculously, his descendants, B'nei Yisrael, would only be able to survive as long as they merited a continuation of this miracle. Therefore, the Akeida had to occur in which Yitzchak was "reborn" to assure the eternal existence of the Jewish people. Malbim quotes a Midrash that Yitzchak's soul actually left him and returned. This rebirth would allow for B'nei Yisrael to survive eternally even if they did not merit the continued miracle. (See Malbim for further elaboration.) Perhaps we can add to the Malbim's words that in the merit of Yitzchak's enormous act of devotion to Hashem - demonstrating his willingness to give up his life to fulfill Hashem's command - Yitzchak's descendants merited unconditional, eternal existence.
Rambam in Iggeres T'chiyas HaMeisim indicates that miraculous acts, unlike the natural order, ordinarily only last for a relatively short period of time. Perhaps we can suggest that it is for this reason that the Shunamite woman's son, miraculously born, died at a young age and Yitzchak had to be "reborn". Only significant acts of devotion to Hashem would cause continuation of the miracle. It was only in the merit of Yitzchak's self-sacrifice that gave Yitzchak and his descendants eternal existence. Similarly, as Meshech Chachma notes, it was the merit of the Shunamite woman's unquestioning belief in the power of Hashem's emissary, Elisha, that allowed her son to be resurrected. She immediately rushes to Elisha to inform him of her son's death with supreme confidence that Elisha, as G-d's prophet, would be able to do anything with Divine consent, even another great miracle. This explains why she remained with Elisha and did not follow Geichazi, Elisha's servant, who was initially sent with Elisha's staff to resurrect the child; the woman trusted Elisha, not Geichazi, who had demonstrated earlier his lack of sanctity. (See Meshech Chachma for further elaboration.)
We can generalize these ideas. Hashem continuously grants us gifts that transcend His natural order: the Exodus from Egypt, the Giving of the Torah, the defiance of all rules of history in preserving K'lal Yisrael. The miraculous, though, is only temporary, unless it is coupled by a demonstration by the recipients of the miracle that they are deserving of the continued miracle. Rav Shalom Noach Berzovsky, in his Nesivos Shalom, explains similarly that this is why tefila, which ultimately is a request of Divine mercy - not based on our actions - would not have been effective in bringing about the Splitting of the Sea. (See Rashi B'Shalach 14:15). Only the act of trust in G-d demonstrated by Nachshon and his followers, who thrust themselves into the water, trusting that G-d would save them, allowed for the continued existence of K'lal Yisrael. (See Sh'vi'i Shel Pesach: The Climax of Ge'ulas Mitzrayim.)
Rav Meir Goldwicht noted that the Divine presence rested on Har Sinai and left. By contrast, the Divine presence on Har HaMoriya, the Har HaBayit, never left. Why the difference? The hashra'at HaShechina on Mount Sinai was a wholly miraculous act of Divine beneficence, unearned by B'nei Yisrael. Therefore, after the giving of the Torah, the Divine Presence left. Har HaBayit became sanctified through a series of acts of selfless devotion to G-d starting with Adam and his children's korbanot offered there, followed by Avraham's and Yitzchak's transcendent acts of sacrifice for Hashem during the event of the Akeida, followed by King David's enormous efforts at procuring the funds necessary to build a House for G-d's presence in this world. The Divine Presence caused by these great acts is eternal. May we always merit Hashem's miracles through His kindness and their continued existence through our efforts (see Defying Human Nature and Divine Miracles for further elaboration of themes discussed here.)