I am He that liveth, and was dead; and behold, I am alive for evermore, Amen. – Revelation 1:18

The Lord in the glory of His tenderness mentions…His atoning death. He says, “I was dead,” the original more correctly rendered is “was made dead.” Here we come upon the human nature of our Redeemer. As God and as man He had two natures, but He was not two persons. As one person He ever lives, and yet He was made to die. He came into this world in human form that He might be capable of death; the pure spirit of God could not die, it was not possible that He, the I AM, could be subject to death; but He allied Himself with humanity, and in that human form Jesus could die, and did die. In very deed, and truth, and not in semblance; Jesus bowed His head, and gave up the ghost, and they laid His corpse in the tomb of Joseph of Arimathea. Here to the child of God is a fruitful source of consolation. He died, then the atonement is complete; without the shedding of blood there is no remission, but the death of the Son of God brings plenteous pardon. There must be in the death of such a one of sufficient merit to remove guilt and cleanse transgression. Is it not written, “He hath washed us from our sins in His own blood?” Dost thou not hear that song in heaven? Will not its music make thee glad? His own blood hath washed thee; if thou believest in Him thou art clean. Look to Calvary, and as thou lookest there and perceivest that He was dead, “fear not.”

And then the master declared His endless life, “I am alive for evermore.” He who offered up the atonement lives again to claim the effect of His sacrifice. He has presented the meritorious sacrifice, and now He has gone to heaven to plead the sacrifice before the throne of God, and to lay claim to the place which He has prepared for them that love Him. Thou hast no dead Savior to trust to: thou reliest in Him who once died-this is comfort to thee, but He lives, the great Redeemer lives. He has risen from the tomb; He has climbed the hills of heaven; He sits at the right hand of the Father, prepared to defend His people. If thou hadst a Christ in the sepulcher that were sorrow upon sorrow; but thou hast a Christ in heaven, who can die no more. Be thou of good cheer. ~ C.H. Spurgeon

https://www.blueletterbible.org/comm/spurgeon_charles/sermons/1028.cfm

And He laid His right hand upon me, saying unto me, Fear not; I am the first and the last: I am He that liveth, and was dead; and behold, I am alive for evermore, Amen. – Revelation 1:17,18

As to the Lord’s person, Jesus revealed to His disciple that He was most truly divine. “I am the first and the last.” This language can be used of none but God Himself; none but He is first; none but He is last; none but God can be first and last. Now, our Lord Jesus Christ was evidently first. He existed before He was born into the world. We read, “a body hast Thou prepared Me.” Then Christ was a previously existing one for whom that body was prepared; and He it is who said, “Lo, I come, to do Thy will O God.” He came into the world, but He had from old eternity dwelt in the bosom of the Father. John the Baptist was born into the world before the Savior, of whom he was the forerunner, but what does he say? His testimony is “He, coming after me, is preferred before me, for He was before me.” He is first in order of honor because first in order of existence. John was the elder as man, but as God the Lord Jesus is from everlasting. Go back in history as far as you will; with one leap ascend to the days of Moses, and there is Christ before you, for we read: “Let us not tempt Christ as some of them also tempted and were destroyed of serpents.” There was Christ, then, in the wilderness vexed by the people. He it was whose voice then shook the earth, but who will yet shake not the earth only but also heaven.

By the words “the first and the last” are signified, in most languages, the sum and substance of all things. We say sometimes the top and the bottom of it is so and so; we mean that it is the whole of it. And the Greeks were wont to say, “This is the prow and stern of the business,” meaning that it is the whole. And so Jesus Christ, in being first and last, is all in all. And, truly, it is so in the working of redemption and salvation; He begins, carries on, completes; He asks no creature help and will have none. To us He is the author and the finisher of our faith, the alpha of our first comfort, and the omega of our final bliss. ~ C.H. Spurgeon

 https://www.blueletterbible.org/comm/spurgeon_charles/sermons/1028.cfm