Then will I remember My covenant with Jacob, and also My covenant with Isaac, and also My covenant with Abraham will I remember; and I will remember the land. Vayikra 26:42
Yitzchak Avinu was not actually sacrificed by Avraham Avinu, and his ashes were not actually placed on the mizbaech-altar. In fact, Yitzchak was 37 years old at the time, and went on to live a further 143 years after the Akeidah, fathered children, and is buried in Me’earas Hamachpelah—the Cave of the Patriarchs in Chevron. What then is the meaning of this chazal which place his ashes on the mizbeach, as if he was actually sacrificed?
The ashes of the ram which was actually sacrificed by Avraham, instead of Yitzchak, are considered “as if” they are the ashes of Yitzchak, as the Torah states:
And Abraham went and took the ram, and offered him up for a burnt-offering in the stead of his son. Breishis 22:13.
The Torah emphasizes that the ram was offered תַּחַת בְּנוֹ– in the stead of his son, which creates the symbolic image that Yitzchak himself was slaughtered, and burned before Hashem. Rashi, on Breishis 22:14, (quoting Breishis Rabba 56:9), states: Instead of his son: Since it is written: “and offered it up for a burnt offering,” nothing is missing in the text. Why then [does it say]: “instead of his son”? Over every sacrificial act that he performed, he prayed, “May it be [Your] will that this should be deemed as if it were being done to my son: as if my son were slaughtered, as if his blood were sprinkled, as if my son were flayed, as if he were burnt and reduced to ashes.”
It is apparent that Yitzchak began to live, after he symbolically died on the Mizbeach. How does one die “symbolically?”
The meaning here is that when Avraham offered the ram in place of his son, Yitzchak’s mindset, at that moment, was to offer up his entire being to God. When the ram was offered, Yitzchak willed that it would be he, who would be sacrificed, and wished that every dimension of his psyche would be aligned with God’s Will. This kavannah—intent, raised Yitzchak to the level of becoming the Amud ha’Avodah-Pillar of Serving God, which forms the foundation of prayer and Avodas Hashem. At that moment, on the level of kavannah-intention, Yitzchak was actually offered on the mizbeach and his ashes do spiritually reside there. 
The strength in Klal Yisrael for one to be moser nefesh–self sacrificing, to God, is based on Yitzchak’s willingness and desire to serve Hashem, wholeheartedly, at the Akeidah. Since Yitzchak was considered an olah temimah–a complete offering, Hashem never, thereafter, allowed him to leave Eretz Yisrael, even though both Avraham, and Yaakov were allowed to do so.
One of the names by which Klal Yisrael is known, namely Efraim, is sourced in the word efer—ashes. There were two Patriarchs who humbled themselves to the point of becoming efer—ashes—as the Torah states concerning Avraham:
And Avraham answered and said: ‘Behold now, I have taken upon me to speak unto the LORD, who am but dust and ashes. Breishis 18:27
The ashes of Yitzchak, behold, reside there.
Since both Avraham and Yitzchak humbled themselves to such an extent that they become like ashes before God, the name אֶפְרַיִם—Efraim—meaning ashes, in the plural—two sets of ashes—became the name which describes the essence of the Jewish nation, connoting their ability to humble themselves before God.
That is what the navi means when he says:
Is Ephraim a darling son unto Me? Is he a child that is dandled? For as often as I speak of him, I do earnestly remember him still; therefore My heart yearns for him, I will surely have compassion upon him, says the LORD. Yirmiyahu 31:19
Klal Yisrael is considered a beloved child of God because of the Akeidah, and Klal Yisrael has an ongoing intrinsic connection to the humility of Avraham and Yitzchak at the Akeidah, by carrying the name –Efraim.
The Talmud states that in a dialogue between Yitzchak and Hashem, Yitzchak said:
I offered myself up before You [as a sacrifice]!’ Shabbos 89b
Yitzchak offered his entire will, psyche and being to God, at the Akeidah. He took everything that God had given to him, and gave it back to God. He gave himself back to God at the Akeidah. He effectively “died” at the Akeidah, and when he came down from the mizbeach, he continued to live—but now he lived a life of total dedication, loyalty and service of Hashem; he no longer had any will of his own. The name Yitzchak means keitz chai–the end of life. Thus, Yitzchak became the ultimate eved Hashem—servant of God.
An eved—servant, is a person who dedicates his life to follow, and perform the will of his master. Yitzchak, at the Akeidah, singularly aligned his will with the Will of the Creator. He was ‘alone” with God at the Akeidah. No human being came closer to God’s Will than Yitzchak, who was willing to give everything he had, to God. Yitzchak reasoned that he owed his very existence to God, and if God wanted his soul back, then he would wholeheartedly return it to Him. Alone in service of God at the Akeidah, Yitzchak became one with God. When we feel alone in the world, and realize, at that moment, that we are an eved Hashem, we attach our aloneness to God. At that moment, in that consciousness, we are not alone, at all. We are in the safest, and most connected state possible. Alone, with God.
 Michtav M’Eliyahu
 Zevachim 62a
 Tikunei Zohar Chadash 26:74.
This essay is an excerpt from Alone Against the World, by Rabbi Yisroel Rollhttp://www.feldheim.com/authors/roll-rabbi-yisroel.html